Channel DC/DC Converters RT9911 complete power-supply solution di
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RT9911
Channel DC/DC Converters
RT9911 complete power-supply solution digital still cameras other hand-held devices. integrates selectable Boost/Buck DC-DC converter, highefficiency step-down DC-DC converter, high-efficiency main step-up converter, converter positive voltage, inverter negative voltage white driver backlight. RT9911 targeted applications that either three primary cells single lithium-ion battery. RT9911 available VQFN-40L 6x6. Each DC-DC converter independent shutdown input.
Features
1.6V 5.5V Battery Input Voltage Range Synchronous Boost/Buck Selectable DC-DC Converter Internal Switches Efficiency Syn-Buck DC-DC Converters 0.8V 5.5V Adjustable Output Voltage Efficiency 100%(MAX) Duty Cycle Internal Switches Main Boost DC-DC Converter Adjustable Output Voltage Efficiency Converter Positive Voltage Inverter Negative Voltage White Driver Panel Backlight 1.4MHz Adjustable Switching Frequency Supply Current Shutdown Mode External Compensation Network Converters Independent Enable Shutdown Each Channel. 40-Lead VQFN Package RoHS Compliant 100% Lead (Pb)-Free
Ordering Information
RT9911 Package Type VQFN-40L (V-Type) -Operating Temperature Range Free with Commercial Standard Green (Halogen Free with Commercial Standard)
Note Richtek Pb-free Green products RoHS compliant compatible with current requirements IPC/JEDEC J-STD-020. Suitable SnPb Pb-free soldering processes. 100% matte (Sn) plating.
Configurations
(TOP VIEW)
SELECT COMP2 PVDD2
Applications
Digital Still Camera Protable Device
VREF VDDM COMP1 PGND1
PGND2 COMP3 DRN3 DRP3 VFB6 CFB6 COMP6
COMP5
COMP4
PVDD1
PVDD5
VQFN-40L DS9911-04 August 2007 www.richtek.com
PVDD3
EXT5
EXT4
EXT6
RT9911
Typical Application Circuit
VBAT VBAT 1.8V 3.2V 10uFx2 3.3V 3.3V SELECT PVDD1 VDDM EXT4 10uF 4.7uH SS0520 10uF 100pF 2.2M 205k
4.7uH
20mA
10uFx4 470k
100pF
3.3V 500mA
510k
0.1uF
150k
PGND1 PGND2
3.3V RT9911 PVDD5 EXT5
VBAT 10uF SS0520 100pF 125k VBAT 10uF 3.3uH -8V/40mA 10uFx2 4.7uF
VCORE 1.8V 300mA
4.7uH 10uF 240k 300k 100pF
PVDD2
VREF Bottom
3.3V
10uF VBAT 10uFx2 4.7uH
PVDD3
4.7uH SS0520 4.7uF 300k
Motor 500mA
EXT6 VFB6 CFB6
100pF 470k
10uFx4
DRN3 DRP3 COMP1 COMP2 COMP3 COMP4 COMP5 COMP6
90.9k
Figure Application Circuit 2-Cells Battery Supply
Note Bottom pad, short (GND). Please remove when Async Boost remove when Sync Boost.
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RT9911
VBAT VBAT 3.4V 4.2V 10uFx2 4.7uH 10uFx4 150k VBAT 10uFx2 2.5V 0.1uF 510k 10uFx2 226k 470k 4.7uH 100pF VREF PGND1 PGND2 Bottom EXT6 VFB6 CFB6 VBAT 10uF 470k 100pF PVDD2 RT9911 PVDD5 EXT5 PVDD1 VBAT SELECT VDDM EXT4 10uF 4.7uH SS0520 10uF 100pF 2.2M
20mA
3.3V 500mA
VBAT 10uF SS0520 100pF 125k 3.3uH
205k
10uF 4.7uF
40mA
2.5V 250mA
PVDD3
VBAT
4.7uH SS0520 4.7uF 300k
10uFx2
Motor 500mA
4.7uH
10pF
470k
10uFx4
DRN3 DRP3 COMP1 COMP2 COMP3 COMP4 COMP5 COMP6
90.9k
Figure Application Circuit Li-ion Battery Supply
Note Bottom pad, short (GND). Please remove when Async Boost remove when Sync Boost. Output voltage setting CH1: 0.8Vx(1+R1/R2) 3.3V 0.8x(1+470k/150k) CH2: 0.8Vx(1+R4/R5) 2.5V 0.8x(1+470k/226k) CH3: 0.8Vx(1+R8/R9) MOTOR 0.8x(1+470k/90.9k) CH4: 1.0Vx(1+R10/R11) 1.0x(1+2.2M/205k) CH5: -1.0Vx(R13/R14) -1.0x(1M/125k) DS9911-04 August 2007 www.richtek.com
RT9911
Functional Description
Name Function Analog Ground -Internal State Shut Down -GND
Configuration
External Switch Control. Frequency Setting Pin. Frequency 500kHz connected. Device Input Power Analog Ground
High Impedance
VDDM
VDDM
Pull
VDDM 1.0V
VREF
1.0V Reference
High Impedance
VREF
COMP1 PGND1 PVDD1 COMP5 EXT5
Feedback Input CH1. Feedback Compensation CH1. Power Ground CH1. Switch Node CH1. Power Input CH1. Feedback Compensation CH5. Feedback Input CH5. External Power Switch CH5. Power Input CH4, CH6. Feedback Compensation CH4. Feedback Input CH4.
-OUT
High Impedance Pull -High Impedance -Pull High Impedance
0.8V
COMP1
PVDD1
PGND1 COMP5
PVDD5
Pull High
EXT5
PVDD5 COMP4
-Pull High Impedance
1.0V
COMP4
continued
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RT9911
Name Function Internal State Shut Down Configuration
PVDD5
EXT4
External Power Switch CH4.
Pull
EXT4
PVDD5
EXT6
External Power Switch CH6.
Pull
EXT6
PVDD3
Power Input CH3.
PVDD3
DRP3
External PMOS Switch CH3. Feedback Compensation CH6. Current Feedback Input CH6.
Pull High
DRP3
COMP6 CFB6
Pull High Impedance
0.2V CFB6
COMP6
VFB6 1.0V
VFB6
Voltage Feedback Input CH6.
High Impedance
50uA
PVDD3
DRN3
External NMOS Switch CH3.
Pull
DRN3
VDDM
Current Sense Input
High Impedance
continued
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RT9911
Name COMP3 PGND2 PVDD2 COMP2 Function Feedback Compensation Feedback Input CH3. Power Ground Switch Node Power Input CH2. Feedback Compensation CH2. Feedback Input CH2. -OUT Internal State Shut Down Pull High Impedance -High Impedance -Pull High Impedance
VDDM 0.8V
Configuration
0.8V COMP3
PVDD2
PGND2
COMP2
Boost/Buck Selection Pin. SELECT Logic state can't changed during operation.
Pull
SELECT
VDDM
Enable Input CH1.
Pull
VDDM
Enable Input CH2.
Pull
continued
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RT9911
Name Function Internal State Shut Down Configuration
VDDM
Enable Input CH3.
Pull
VDDM
Enable Input CH4.
Pull
VDDM
Enable Input CH5.
Pull
VDDM
Enable Input CH6.
Pull
exposed must soldered Exposed (41) large connected maximum power dissipation.
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RT9911
Function Block Diagram
VDDM
PVDD5 EXT4 COMP4 1.0V PVDD5 EXT5 Inverter 0.8V V-Mode Step-Up
SELECT PVDD1 C-Mode Step-Up Step-Down
PGND1 COMP1
COMP5
1.0V C-Mode Step-Down
PVDD2
VREF
Switch Controller 0.8V PVDD5 EXT6 WLED 50uA 1.0V
PGND2 COMP2
PVDD3 DRP3 C-Mode Step-Up
VFB6
PVDD3 DRN3
COMP6 CFB6 0.2V Oscillator Thermal Shutdown
0.8V
COMP3
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RT9911
Absolute Maximum Ratings
(Note Supply Voltage, VDDM -0.3V Power Switch -0.3V (VDD 0.3V) Other Pins -0.3V Power Dissipation, 25°C VQFN-40L -Package Thermal Resistance (Note VQFN-40L 6x6, -Junction Temperature -Lead Temperature (Soldering, sec.) -Storage Temperature Range -ESD Susceptibility (Note (Human Body Mode) (Machine Mode) -2.778W 36°C/W 150°C 260°C -65°C 150°C 200V
Recommended Operating Conditions
(Note
Dimming Control Frequency Range, 300Hz 900Hz Supply Voltage, VDDM 2.4V 5.5V Junction Temperature Range -40°C 125°C Operation Temperature Range -40°C 85°C
Electrical Characteristics
(VDDM 3.3V, 25°C, unless otherwise specified)
Parameter Supply Voltage VDDM Minimum Startup Voltage VDDM Operating Voltage VDDM Over Voltage Protection Supply Current
Symbol VDDM (Note
Test Conditions
-2.4
-6.5
Units
VDDM Voltage
Shutdown Supply Current into VDDM IOFF (Sync-Boost Syn-Buck) Supply Current into VDDM (Sync-Buck) Supply Current into VDDM (Sync-Boost) Supply Current into VDDM (Asyn-Boost) Supply Current into VDDM (Asyn-Inverter) Supply Current into VDDM (Asyn-Boost) Supply Current into VDDM
VDDM 3.3V, Non-Switching VDDM 3.3V, Non-Switching VDDM 3.3V, Non-Switching VDDM 3.3V, Non-Switching VDDM 3.3V, Non-Switching VDDM 3.3V, Non-Switching
continued
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RT9911
Parameter Oscillator Operation Frequency Maximum Duty Cycle (Boost) Maximum Duty Cycle (Buck) Maximum Duty Cycle Maximum Duty Cycle Maximum Duty Cycle Maximum Duty Cycle Maximum Duty Cycle Feedback Regulation Voltage Feedback Regulation Voltage FB1, FB2, Feedback Regulation Voltage @FB4 Feedback Regulation Voltage VFB1, VFB4 VFB5 0.788 0.98 -0.18 0.984 IREF 100uA -0.8 -0.2 0.812 1.02 -0.22 1.016
Symbol fOSC DMAX1 DMAX1 DMAX2 DMAX3 DMAX4 DMAX5 DMAX6
Test Conditions Open SELECT 3.3V, VFB1 0.7V SELECT VFB1 0.7V VFB2 0.7V VFB3 0.7V VFB4 0.9V VFB5 0.1V VCFB6 0.18V, VFB6 0.9V
Units
Feedback Regulation Voltage VFB6 VVFB6 Feedback Regulation Voltage CFB6 VCFB6 Reference VREF Output Voltage VREF Load Regulation Error Amplifier (CH1, CH2, CH3, CH4, CH5, CH6) Compensation Source Current (CH1, CH2, CH3, CH4, CH5, CH6) Compensation Sink Current (CH1, CH2, CH3, CH4, CH5, CH6) Power Switch Resistance MOSFET Switch Current Limitation (Buck) Switch Current Limitation (Boost) Resistance MOSFET Switch Current Limitation Resistance DRN3 Resistance DRP3 RDS(ON)NP3 P-MOSFET, PVDD3 3.3V RDS(ON)NN3 N-MOSFET, PVDD3 3.3V RDS(ON)PP3 P-MOSFET, PVDD3 3.3V RDS(ON)PN3 N-MOSFET, PVDD3 3.3V RDS(ON)P4 P-MOSFET, PVDD3 3.3V RDS(ON)N4 N-MOSFET, PVDD3 3.3V RDS(ON)P1 P-MOSFET, PVDD1 3.3V RDS(ON)N1 N-MOSFET, PVDD1 3.3V SELECT=0 SELECT=1 RDS(ON)P2 P-MOSFET, PVDD2 3.3V RDS(ON)N2 N-MOSFET, PVDD2 3.3V VREF
-1.3 -1.3
Resistance MOSFET
continued
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RT9911
Parameter Power Switch Resistance MOSFET RDS(O N)P5 P-MOSFET, 3.3V RDS(O N)N5 N-MOSFET, 3.3V RDS(O N)P6 P-MOSFET, 3.3V RDS(O N)N6 N-MOSFET, 3.3V ICS3 IVFB Symbol Test Conditions Units
Resistance MOSFET Switch Controller Sink Current External Current Setting (CH3) Sourcing Current VFB6 Sink Current Protection Under Voltage Protection Threshold Voltage FB1, Over Voltage Protection FB1, Control EN1, EN2, EN3, EN4, EN5, Input High Level Threshold EN1, EN2, EN3, EN4, EN5, Input Level Threshold EN1, EN2, EN3, EN4, EN5, Sink Current Select Input High Level Threshold Select Input Level Threshold Select Sink Current Thermal Protection Thermal Shutdown Thermal Shutdown Hysteresis
SELECT SELECT
VDDM 3.3V VDDM 3.3V VDDM 3.3V
-0.4 -0.4
ISELECT
-125
Note Stresses listed above "Absolute Maximum Ratings" cause permanent damage device. These stress ratings. Functional operation device these other conditions beyond those indicated operational sections specifications implied. Exposure absolute maximum rating conditions extended periods remain possibility affect device reliability. Note Devices sensitive. Handling precaution recommended. Note device guaranteed function outside operating conditions. Note measured natural convection 25°C effective thermal conductivity test board JEDEC 51-3 thermal measurement standard. Note Schottky retifier connected from PVDD1 required low-voltage startup, refer Figure
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RT9911
Typical Operating Characteristics
Boost Efficiency Output Current
Buck Efficiency Output Current
Efficiency
3.2V 2.5V 2.0V 1.5V
Efficiency
3.0V 3.4V 3.8V 4.5V
Boost VOUT 3.3V
1000
Buck VOUT 2.5V
1000
Output Current (mA)
Output Current (mA)
Boost Output Voltage Ripple
1.8V, VOUT 3.3V, IOUT 100mA
Buck Output Voltage Ripple
4.2V, VOUT 3.3V, IOUT 100mA
VOUT (10mV/Div)
(2V/Div)
Time (1s/Div)
VOUT (10mV/Div)
(2V/Div)
Time (1s/Div)
Boost Load Transient Response
3.0V, VOUT 3.3V
Buck Load Transient Response
4.2V, VOUT 3.3V
VOUT (100mV/Div)
IOUT (100mA/Div)
Time (1ms/Div)
IOUT (200mA/Div)
VOUT (100mV/Div)
Time (1ms/Div)
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RT9911
Boost Output Voltage VDDM Voltage
3.30 3.29
Buck Output Voltage Output Current
3.375 3.374
Output Voltage
Output Voltages
3.28 3.27 3.26 3.25 3.24 3.23 3.22 3.21 3.20
3.373 3.372 3.371 3.370 3.369 3.368 3.367 3.366 3.365
2.5V, VOUT 3.3V, IOUT 250mA
3.7V, VOUT 3.3V
VDDM Voltage
Loading Current (mA)
Boost Output Voltage Output Current
3.330 3.329 3.328
Buck Efficiency Output Current
Output Voltages
3.326 3.325 3.324 3.323 3.322 3.321 3.320
Efficiency
3.327
2.5V 3.0V 3.8V 4.5V
2.4V, VOUT 3.3V
VOUT 1.8V
1000
Output Current (mA)
Output Current (mA)
Output Voltage Ripple
3.3V, VOUT 1.8V, IOUT 300mA
Output Voltage Ripple
4.2V, VOUT 2.5V, IOUT 400mA
VOUT (10mV/Div)
(2V/Div)
Time (1s/Div)
VOUT (10mV/Div)
(2V/Div)
Time (1s/Div)
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RT9911
Load Transient Response
3.0V, VOUT 2.5V
Load Transient Response
3.3V, VOUT 1.8V
VOUT (20mV/Div)
IOUT (200mA/Div)
Time (1ms/Div)
IOUT (100mA/Div)
VOUT (20mV/Div)
Time (1ms/Div)
Load Transient Response
4.2V, VOUT 2.5V
1.84 1.83 1.82
Output Voltage VDDM Voltage
3.3V, VOUT 1.8V, IOUT 250mA
VOUT (20mV/Div)
Output Voltage
1.81 1.80 1.79 1.78 1.77 1.76 1.75 1.74
IOUT (200mA/Div)
Time (1ms/Div)
VDDM Voltage
Buck Output Voltage Output Current
3.370 3.360
Buck Output Voltage Output Current
1.815 1.814
Output Voltages
Output Voltages
3.350 3.340 3.330 3.320 3.310 3.300 3.290 3.280 3.270
1.813 1.812 1.811 1.810 1.809 1.808 1.807 1.806 1.805
3.7V, VOUT 3.3V
1000
3.7V, VOUT 1.8V
1000
Output Current (mA)
Output Current (mA)
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RT9911
Boost Efficiency Output Current
Boost Efficiency Output Current
Efficiency
Efficiency
3.2V 2.5V 2.0V 1.5V
4.5V 3.8V 3.2V 2.5V 2.0V 1.5V
VOUT 3.3V
1000
VOUT
1000
Output Current (mA)
Output Current (mA)
Boost Efficiency Output Current
Output Voltage Ripple
1.8V, VOUT 3.3V, IOUT 400mA
Efficiency
VOUT 3.3V
1000
VOUT (20mV/Div)
3.0V Async 2.4V Async 1.5V Async 3.0V Sync 2.4V Sync 1.5V Sync
(2V/Div)
Time (1s/Div)
Output Current (mA)
Output Voltage Ripple
Load Transient Response
3.0V, VOUT 3.3V
VOUT (20mV/Div)
1.8V, VOUT IOUT 350mA
IOUT (200mA/Div)
VOUT (100mV/Div)
(2V/Div)
Time (1s/Div)
Time (1ms/Div)
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RT9911
Boost Output Voltage VDDM Voltage
3.30 3.29 3.28
Boost Output Voltage VDDM Voltage
5.08 5.07 5.06
2.5V, VOUT 3.3V, IOUT 250mA
2.5V, VOUT 5.0V, IOUT 250mA
Output Voltage
3.27 3.26 3.25 3.24 3.23 3.22 3.21 3.20
Output Voltage
5.05 5.04 5.03 5.02 5.01 5.00 4.99 4.98
VDDM Voltage
VDDM Voltage
Boost Output Voltage Output Current
5.020 5.015
Boost Efficiency Output Current
3.7V, VOUT
Output Voltage
5.010
Efficiency
5.005 5.000 4.995 4.990 4.985 4.980 4.975
4.5V 3.8V 3.2V 2.5V 2.0V 1.5V
VOUT
Output Current
Output Current (mA)
Output Voltage Ripple
1.8V, VOUT 12V, IOUT 30mA
Load Transient Response
1.8V, VOUT
VOUT (20mV/Div)
(5V/Div)
IOUT (20mA/Div)
VOUT (100mV/Div)
Time (1s/Div)
Time (1ms/Div)
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RT9911
Output Voltage VDDM Voltage
11.88 11.87 11.86
Output Voltage VDDM Voltage
15.42 15.41 15.40
2.5V, PVDD5 3.3V, IOUT 30mA
2.5V, PVDD5 3.3V, IOUT 30mA
Output Voltage
11.85 11.84 11.83 11.82 11.81 11.80 11.79 11.78
Output Voltage
15.39 15.38 15.37 15.36 15.35 15.34 15.33 15.32
VDDM Voltage
VDDM Voltage
Boost Output Voltage Output Current
15.780 15.775
Inverting Efficiency Output Current
3.7V, VOUT 15.5V
Output Voltages
15.770
15.760 15.755 15.750 15.745 15.740 15.735 15.730
Efficiency
15.765
1.5V 2.0V 2.5V 4.5V 3.2V 3.8V
VOUT
Output Current (mA)
Output Current (mA)
Output Voltage Ripple
1.8V, VOUT -8V, IOUT 50mA
Load Transient Response
1.8V, VOUT
(5V/Div)
VOUT (20mV/Div)
IOUT (20mA/Div)
VOUT (100mV/Div)
Time (1s/Div)
Time (1ms/Div)
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RT9911
Output Voltage VDDM Voltage
-8.02 -8.03 -8.04
Output Voltage VDDM Voltage
-6.02 -6.03 -6.04
3.0V, PVDD5 3.3V, IOUT 30mA
3.0V, PVDD5 3.3V, IOUT 30mA
Output Voltage
Output Voltage
-8.05 -8.06 -8.07 -8.08 -8.09 -8.10 -8.11 -8.12
-6.05 -6.06 -6.07 -6.08 -6.09 -6.10 -6.11 -6.12
VDDM Voltage
VDDM Voltage
Output Voltage Output Current
-8.152 -8.151 -8.150
Efficiency Input Voltage
Output Voltages
Efficiency
-8.149 -8.148 -8.147 -8.146 -8.145 -8.144 -8.143 -8.142 -100
IOUT 20mA
3.7V, VOUT
Loading Current (mA)
Input Voltage
Output Voltage Ripple
1.8V, VOUT WLED, IOUT 20mA
Load Transient Response
2.5V, VOUT 1.8V
VOUT (20mV/Div)
(5V/Div)
Time (1s/Div)
IOUT (200mA/Div)
VOUT (10mV/Div)
Time (1ms/Div)
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RT9911
Power Sequence
EN1/EN2 (2V/Div) EN4/EN5 (2V/Div)
Power Sequence
VOUT_Ch1 (2V/Div)
VOUT_Ch2 (2V/Div)
Start 2.5V
VOUT_Ch5 (5V/Div)
VOUT_Ch4 (5V/Div)
Start 2.5V
Time (1ms/Div)
Time (2ms/Div)
Feedback Voltage Temperature
1.04 1.00
Feedback Voltage
VFB4, VFB6
0.96 0.92 0.88 0.84 0.80 0.76 0.72
VFB1, VFB2, VFB3
Temperature (°C)
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RT9911
Applications Information
RT9911 includes following DC/DC converter channels build multiple-output power-supply system. Selectable step-up step-down synchronous current mode DC/DC converter with internal power MOSFETs. Step-down synchronous current mode DC/DC converter with internal power MOSFETs. Step-up asynchronous current mode DC/DC controller drive external power MOSFETs. Step-up asynchronous voltage mode DC/DC controller. Inverting DC/DC voltage mode controller. DC/DC voltage mode controller WLED well conventional boost application; provides open protection. Selectable Step-up Step-down Converter selectable step-up (SELECT logic high) step-down (SELECT logic low). Step-up With internal MOSFETs synchronous rectifier, efficiency 95%. converter always operates fixed frequency mode (continuous current mode). Step-down With internal MOSFETs synchronous rectifier, efficiency 95%. converter always operates fixed frequency mode CCM. While input voltage close output voltage, converter enters dropout mode. Duty could long 100% extend battery life. Figure 3(a) detailed functional block. Step-down DC/DC Converter With internal MOSFETs synchronous rectifier, efficiency 95%. converter always operates fixed frequency mode CCM. While input voltage close output voltage, converter enters dropout mode. Duty could long 100% extend battery life. Figure 3(b) detailed functional block. Step-up DC/DC Controller With external MOSFETs synchronous rectifier, efficiency 97%. converter always operates fixed frequency mode CCM. threshold current limit estimated RDS(ON) external NMOS. Protections detailed information detailed functional block Figure 3(c). CH4, Step-up DC/DC Controller fixed frequency voltage mode controllers. EXT4 EXT6 pins designed drive external NMOS switch. optimized WLED application. CFB6 current-sensing feedback, VFB6 provides over voltage protection (WLED open circuit). Protections detailed information detailed functional block Figure CH6). Inverting Controller voltage mode, fixed frequency controller generate negative output voltage. EXT5 designed drive external PMOS switch. turn PMOS completely, please note that PVDD5 should lower than source voltage PMOS. Figure 3(f) detailed functional block. Reference Voltage RT9911 provides precise reference voltage with souring capability 100uA. Connect ceramic capacitor from VREF GND. Reference voltage enabled connecting logic high.
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RT9911
PVDD1 COMP1 0.8V SELECT
PVDD2 COMP2 0.8V
Logic
Driver
Logic
Driver
Current Sense Slope compensation Fault Protection PGND1
Current Sense Slope compensation Fault Protection PGND2
Figure 3(a)
Figure 3(b)
PVDD3 COMP3 0.8V
COMP4 1.0V
PVDD5
DRP3 Logic Driver DRN3
Logic
Driver EXT4
Current Sense Slope compensation Fault Protection
PGND2
Triangle Wave
Figure 3(c)
Figure 3(d)
PVDD5 COMP6 CFB6 0.2V
COMP5
PVDD5
Logic
Driver EXT6
Logic
Driver EXT5
Diming Control Triangle Wave Fault Protection
Triangle Wave
Figure 3(e) Figure Detailed Functional Block each channel
Figure 3(f)
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RT9911
VBAT VDDM 3.3V) 3.3V VCORE 1.8V VI/O 3.3V Motor WLED
Note Please refer Figure application Information. Timing sequence should controlled pins.
Figure Timing Diagram
Calculation method: precise value. approximation. Units second, Farad, Compensation capacitor CH6. 0.7V (CH1 Boost) 0.7V (CH1 Buck) 0.35V 0.7V 0.35V 0.85V 0.85V (0.5V 0.48A RDS(ON)_N /1.25uA load (Boost) (0.33V 0.2A RDS(ON)_P /1.25uA load (Buck) (0.33V 0.2A RDS(ON)_P /1.25uA load
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(0.5V 0.8A RDS(ON)_N /3.6uA load (1.0V load (1.0V min. load (0.25V 2.6uA WLEDs where (VBAT 3.3V) (Boost) 3.3V VBAT VVCORE 1.8V VBAT (VBAT VMotor (VBAT VCCD 12V) |VCCD -8V| VBAT |VCCD -8V|) (VBAT VWLED) Example 0.7V (Boost) (0.5 (1-1.8/3.3) 0.48 0.2) 1.25uA
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(Buck)
RT9911
Oscillator internal oscillator synchronizes with fixed operation frequency. frequency could connecting resistor between GND. Figure adjust frequency. Soft Start With internal soft start mechanism, soft start time each channel proportional compensation capacitor. Refer soft start waveform Figure typical application. Protection RT9911 provides versatile protection functions. Protection type, threshold protection methods summarized Table Table
Protection type VDDM CH1: Boost Over Voltage Protection Current Limit Current Limit CH1: Buck Under Voltage Protection Over Voltage Protection Current Limit Under Voltage Protection Over Voltage Protection Thermal Current Limit Over Voltage Protection Thermal shutdown Threshold (typical) Refer Electrical spec VDDM 6.5V NMOS current> 2.5A PMOS current 2.0A 0.4V 1.0V PMOS current 2.0A 0.4V 1.0V 0.3V, below Note VFB6 1.0V, Figure Temperature 180°C Protection methods Disable channels NMOS latched PMOS latched channels shutdown NMOS, PMOS latch channels shutdown NMOS, PMOS latch channels shutdown PMOS latched channels shutdown NMOS, PMOS latch channels shutdown NMOS, PMOS latch channels shutdown NMOS latched NMOS channels stop switching Reset method Restart VDDM 6.5V Automatic reset next clock cycle VDDM power reset VDDM power reset VDDM power reset VDDM power reset VDDM power reset VDDM power reset Automatic reset next clock cycle VFB6 1.0V Temperature 160°C
2500 2250 2000 1750 1500 1250 1000 1000
Oscillator Frequency
Oscillator Frequency (kHz)1
Figure Adjust Frequency
Note RDS(ON) Iinductor 0.3V, then current limit happens. example, select NMOS( AOS3402), RDS(ON) =110m 2.5V), then current limt happens Iinductor 2.73A. DS9911-04 August 2007 www.richtek.com
RT9911
VBAT
VDDM
VBAT
WLED EXT6
10uA DRN3 Iinductor
VFB6 50uA
Figure Current Limit Setting
CFB6
RT9911 Component Selection Compensation Sync-Boost (Select High Logic) sync-boost converter employs current-mode control simplify control loop compensation. There RHPZ (Right Hand Plane Zero) appeared loop-gain frequency response when boost converter operates with continuous inductor current (typically case), also call works (Continuous Current Mode). stability, cross over frequency (fC), unity gain frequency, must lower than this RHPZ frequency. fixed parameters boost compensation follows Transconductance (from COMP), 200us Current sense transresistance, 0.4V/A Feedback voltage, 0.8V
Figure Over Voltage Protection Method (VWLED R+1V, protection happens) input parameters boost compensation follows: voltage divider resistor between VOUT VIN, input voltage. VOUT, desired output voltage IOUT(MAX.), maximum output load FOSC, operating frequency inductance RESR, (Equivalent Series Resistance) COUT (ceramic output capacitor) TDRP(%), Transient droop. results will boost compensation follows: voltage divider resistor between ground. feedforward capacitor parallel with
VOUT
COMP
0.8V
RESR COUT
IOUT
compensation resistor COMP pin. compensation capacitor series with connect ground. connect between COMP ground. (Can ignored 10pF).
Figure
COUT, output capacitance. This compensation based ceramic output capacitor.
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RT9911
major steps getting above results
(VOUT VFB)
RLOAD 6.3nF. VOUT Choose 6.8nF.
Half-load transient means load from 0.25A 0.5A transient. dI=0.5 0.25=0.25A dVFB TDRP(%) 0.04V. Thus,
Find RHPZ(Right Hand Plan Zero) location. RHPZ(Boost) RLOAD RLOAD VOUT IOUT(MAX.) Where VOUT
Duty Cycle
(cross over frequency) sufficiently below RHPZ. example RHPZ/6 LOAD Select based allowed transient droop. dVFB where transient step, dVFB TDRP(%) COUT RLOAD Find ffz, zero ffp, pole ratio voltage divider with VOUT ratio placing therefore ratio where ratio Evaluate canceling zero from COUT (ceramic output capacitor). RESR COUT ignore 10pF. Example 470k, 1.8V, VOUT 3.3V, 0.8V, IOUT(MAX.) 0.5A, fOSC 500kHz, 4.7uH, RESR half-load transient droop Results:
470k 150k VOUT
dVFB
COUT
6.8n RLOAD
ratio
VOUT
126pF, where 2.68kHz ratio
Choose 150pF COUT RESR 0.005 4.8pF which less than 10pF. ignored. Sync-Buck (Select Logic) Sync-Buck sync-buck (select pin=low logic) sync-buck converters employ current-mode control simplify control loop compensation. There RHPZ (Right Hand Plan Zero) buck topology there high frequency pole (cross over frequency) chosen sufficient less than fHP. fixed parameters buck compensation follows: Transconductance (from COMP), 200us Current sense transresistance, 0.3V/A Feedback voltage, 0.8V input parameters buck compensation follows: voltage divider resistor between VOUT
RHPZ(Boost) RLOAD
66.3kHz, where VOUT RLOAD 0.54 IOUT(MAX) VOUT
RHPZ 11kHz
DS9911-04 August 2007
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RT9911
VIN, input voltage. VOUT, desired output voltage IOUT(MAX.), maximum output load fOSC, operating frequency inductance RESR, (Equivalent Series Resistance) COUT (ceramic output capacitor) TDRP(%), Transient droop. results will boost compensation follows: voltage divider resistor between ground. feedforward capacitor parallel with compensation resistor COMP pin. compensation capacitor series with connect ground connect between COMP ground. (Can ignored 10pF) COUT, output capacitance. This compensation based ceramic output capacitor. major steps getting above results VOUT (cross over frequency) sufficiently below fOSC. example
RLOAD VOUT
Evaluate canceling zero from COUT (ceramic output capacitor). COUT RESR ignore 10pF. Example 470k, VOUT 1.8V, 0.8V, IOUT(MAX.) 0.5A, fOSC 500kHz, 4.7uH, RESR half-load transient droop
Results
470k 376k VOUT
fOSC 40kHz
RLOAD 4.25nF, where VOUT VOUT RLOAD IOUT(MAX.)
Choose 4.7nF. Half-load transient means load from 0.25A 0.5A transient. 0.25=0.25A dVFB TDRP(%) 0.04V. Thus,
9.4k choose dVFB
COUT 3.9nF 10.8 Choose RLOAD ratio
VOUT 2.25
dVFB where transient step, dVFB TDRP(%)
RLOAD Find ffz, zero ffp, pole ratio voltage divider with VOUT ratio placing therefore ratio where ratio COUT
15.2pF, where 22.2kHz ratio 2.25
Choose 22pF COUT RESR 0.005 which less than 10pF. ignored.
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RT9911
Boost Controller with External MOSFET boost controller driving external logic level MOSFET employs current-mode control simplify control loop compensation. There RHPZ (Right Hand Plan Zero) appeared loop-gain frequency response when boost converter operates with continuous inductor current (typically case), also call works (Continuous Current Mode). stability, cross over frequency (fC), unity gain frequency, must lower than this RHPZ frequency. fixed parameters boost compensation follows Transconductance (from COMP), 200us Feedback voltage, 0.8V input parameters boost compensation follows RDS(ON), NMOSFET RDS(ON), which find transresistance, RCS. voltage divider resistor between VOUT VIN, input voltage. VOUT, desired output voltage IOUT(MAX.), maximum output load FOSC, operating frequency inductance RESR, (Equivalent Series Resistance) COUT (ceramic output capacitor) TDRP(%), Transient droop. results will boost compensation follows RCS, transresistance current sense. voltage divider resistor between ground. feedforward capacitor parallel with compensation resistor COMP pin. compensation capacitor series with connect ground connect between COMP ground. (Can ignored 10pF)
DS9911-04 August 2007 www.richtek.com
COMP
COUT, output capacitance. This compensation based ceramic output capacitor. major steps getting above results RDS(ON) rest steps same sync-boost. Asyn-Boost Controller with External MOSFET asyn-boost controller driving external logic level type MOSFET, which employs voltage mode control regulate output voltage. Compensation depends designing loading range working discontinuous continuous inductor current mode. (DCM CCM). Asyn-Boost call because inductor current falls zero each switch cycle. benefit designing simple loop compensation, which RHPZ (Right Hand Plan Zero) conjugate double pole frequency domain worry about, single load pole instead. However, output ripple efficiency worse than (Continuous Inductor Current). loading around tens design with less impact output ripple efficiency, gain more easy stabilize control loop. fixed parameters asyn-boost compensation follows: Transconductance (from COMP), 200us. Internal voltage ramp decide duty cycle, Feedback voltage,
VOUT
RESR COUT
IOUT
Figure
RT9911
input parameters asyn-boost compensation follows voltage divider resistor between VOUT VIN, input voltage. VOUT, desired output voltage IOUT(MAX.), maximum output load fOSC, operating frequency inductance COUT, output capacitance. This compensation based ceramic output capacitor. RESR, (Equivalent Series Resistance) COUT (ceramic output capacitor) results will asyn-boost compensation follows voltage divider resistor between ground. feedforward capacitor parallel with compensation resistor COMP pin. compensation capacitor series with connect ground connect between COMP ground. (Can ignored 10pF) major steps getting above results VOUT Select suitable inductor ensure IOUT(MIN.) works DCM, which inductor current falls zero each switch cycle. IOUT(MAX.) fOSC sufficient below fOSC. fOSC example: lower Find load pole RLOAD COUT VOUT VOUT where RLOAD IOUT(MAX.) Asyn-boost call because inductor current always continuous operation. benefit designing lower VOUT inductor current ripple higher efficiency from lower coil loss, with expense larger inductor size cost control loop comes with RHPZ (Right Hand Plan Zero) conjugate double pole frequency domain worry about. fixed parameters asyn-boost compensation follows Transconductance (from COMP), 200us Internal voltage ramp decide duty cycle, Feedback voltage, input parameters asyn-boost compensation follows: voltage divider resistor between VOUT VIN, input voltage. VOUT, desired output voltage IOUT(MAX.), maximum output load IOUT(MIN.), minimum output laod fOSC, operating frequency
DS9911-04 August 2007
which duty VOUT transfer function. duty cycle VOUT COUT
RLOAD letting comp zero load pole.
Find ffz, zero ffp, pole ratio voltage divider with VOUT ratio placing therefore ratio
where ratio
Evaluate canceling zero from COUT (ceramic output capacitor). COUT RESR ignore 10pF.
VOUT where Gdod Gdod
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RT9911
inductance COUT, output capacitance. This compensation based ceramic output capacitor. RESR, (Equivalent Series Resistance) COUT (ceramic output capacitor) results will asyn-boost compensation follows: voltage divider resistor between ground. feedforward capacitor parallel with compensation resistor COMP pin. compensation capacitor series with connect ground connect between COMP ground. (Can ignored 10pF) major steps getting above results VOUT Select suitable inductor ensure IOUT(MIN.) works CCM, IOUT(MIN.) fOSC Find RHPZ(Right Hand Plan Zero) location. RHPZ(Boost) RLOAD RLOAD VOUT IOUT(MAX) where VOUT Find placing zero fcdp cancel another double pole. fcdp 10.Evaluate canceling zero from COUT (ceramic output capacitor). RESR COUT ignore 10pF. Asyn-Inverter Controller with External MOSFET asyn-inverter controller driving external logic level type MOSFET, which employs voltage mode control regulate output voltage. Compensation depends designing loading range working discontinuous continuous inductor current mode. (DCM CCM). Asyn-Inverter call because inductor current falls zero each switch cycle. benefit designing simple loop compensation, which RHPZ (Right Hand Plan Zero) conjugate double pole frequency domain worry about, single load pole instead. However, output ripple efficiency worse than (Continuous Inductor Current). loading around tens design with less impact output ripple efficiency, gain more easy stabilize control loop. fixed parameters asyn-inverter compensation follows: Transconductance (from COMP), 200us Internal voltage ramp decide duty cycle, Feedback voltage, Reference voltage, VREF
VOUT
duty cycle
(cross over frequency) sufficiently below RHPZ. RHPZ lower. example Find load pole RLOAD COUT VOUT VOUT where RLOAD IOUT(MAX.)
where Gdoc Gdoc which duty VOUT transfer function. duty cycle VOUT Find fcdp (LC)2 which conjugate double pole from filter. cancel double pole. fcdp
COMP
RESR COUT
IOUT
VREF 4.7uF
Figure
DS9911-04 August 2007 www.richtek.com
RT9911
input parameters asyn-inverter compensation follows voltage divider resistor between VOUT VIN, input voltage. VOUT, desired output voltage IOUT(MAX.), maximum output load fOSC, operating frequency inductance COUT, output capacitance. This compensation based ceramic output capacitor. RESR, (Equivalent Series Resistance) COUT (ceramic output capacitor) results will asyn-inverter compensation follows voltage divider resistor between VREF. feedforward capacitor parallel with compensation resistor COMP pin. compensation capacitor series with connect ground connect between COMP ground. (Can ignored 10pF) major steps getting above results VREF VOUT (-8)V VOUT then 125k (-8) Select suitable inductor ensure IOUT(MIN.) works DCM, which inductor current falls zero each switch cycle. Asyn-Inverter call because inductor current always continuous operation. benefit designing lower VOUT inductor current ripple higher efficiency from lower coil loss, with expense larger inductor size cost control loop comes with RHPZ (Right Hand Plan Zero) conjugate double pole frequency domain worry about. fixed parameters asyn-inverter compensation follows Transconductance (from COMP), 200us Internal voltage ramp decide duty cycle, Feedback voltage, Reference voltage, VREF input parameters asyn-inverter compensation follows voltage divider resistor between VOUT VIN, input voltage. VOUT, desired output voltage IOUT(MAX.), maximum output load
DS9911-04 August 2007
VOUT where Gdod Gdod which duty Vout transfer function.
duty cycle
COUT
abs(VOUT) abs(VOUT)
RLOAD letting comp zero load pole.
Find ffz, zero ffp, pole ratio voltage divider with abs(VOUT) VREF ratio VREF placing therefore ratio where ratio Evaluate canceling zero from COUT (ceramic output capacitor). COUT RESR ignore 10pF.
IOUT(MAX.) fOSC
sufficient below fOSC fOSC example: lower Find load pole RLOAD COUT VOUT where RLOAD IOUT(MAX.)
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RT9911
IOUT(MIN.), minimum output laod fOSC, operating frequency inductance COUT, output capacitance. This compensation based ceramic output capacitor. RESR, (Equivalent Series Resistance) COUT (ceramic output capacitor) results will asyn-inverter compensation follows voltage divider resistor between VREF. feedforward capacitor parallel with compensation resistor COMP pin. compensation capacitor series with connect ground connect between COMP ground. (Can ignored 10pF) major steps getting above results VREF VOUT (-8)V VOUT then 125k (-8) Select suitable inductor ensure IOUT(MIN.) works CCM, IOUT(MIN.) fOSC Find RHPZ(Right Hand Plan Zero) location. where RHPZ(Boost) RLOAD VOUT abs(VOUT) RLOAD duty cycle IOUT(MAX) abs(VOUT) (cross over frequency) sufficiently below RHPZ. RHPZ example: lower Find load pole RLOAD COUT abs(VOUT) where RLOAD IOUT(MAX.) where Gdoc Gdoc which duty VOUT transfer function. duty cycle abs(VOUT) VOUT abs(VOUT)
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(LC)2 which conjugate double pole from filter. cancel double pole. fcdp Find placing zero fcdp cancel another double pole. fcdp 10.Evaluate canceling zero from COUT (ceramic output capacitor). COUT RESR ignore 10pF.
Find fcdp
Layout Considerations feedback netwok should very close pin. compensation network should very close COMP avoid through VIA. current sense, should close drain site external NMOS. Keep high current path short possible.
DS9911-04 August 2007
RT9911
Outline Dimension
DETAIL
DETAIL Mark Options Note configuration identifier optional, must located within zone indicated.
Symbol
Dimensions Millimeters 0.800 0.000 0.175 0.180 5.950 4.000 5.950 4.000 0.500 0.350 0.450 1.000 0.050 0.250 0.300 6.050 4.750 6.050 4.750
Dimensions Inches 0.031 0.000 0.007 0.007 0.234 0.157 0.234 0.157 0.020 0.014 0.018 0.039 0.002 0.010 0.012 0.238 0.187 0.238 0.187
V-Type Package
Richtek Technology Corporation
Headquarter Taiyuen Street, Chupei City Hsinchu, Taiwan, R.O.C. Tel: (8863)5526789 Fax: (8863)5526611
Richtek Technology Corporation
Taipei Office (Marketing) 137, Lane 235, Paochiao Road, Hsintien City Taipei County, Taiwan, R.O.C. Tel: (8862)89191466 Fax: (8862)89191465 Email: marketing@richtek.com
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DS9911-04 August 2007
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