TC170 TC170 CMOS CURRENT MODE CONTROLLER Supply Current With CMOS

The Datasheet Archive - 100 Million Datasheets from 7500 Manufacturers.

TC170 TC170 CMOS CURRENT MODE CONTROLLER Supply Current With CMOS

Datasheet Thumbnail

Top Searches for this datasheet

CMOS CURRENT MODE CONTROLLER
TC170 TC170 CMOS CURRENT MODE CONTROLLER
Supply Current With CMOS Technology 3.8mA Internal Reference 5.1V Fast Rise/Fall Times 1000pF) 50nsec Dual Push-Pull Outputs Direct-Power MOSFET Drive High Totem-Pole Output Drive 300mA Differential Current-Sense Amplifier Programmable Current Limit Soft-Start Operation Double-Pulse Suppression Undervoltage Lockout Wide Supply Voltage Operation High Frequency Operation 200kHz Available with State Outputs Power, Pin-Compatible Replacement UC3846
GENERAL DESCRIPTION
TC170 brings low-power CMOS technology current-mode-switching power supply controller market. Maximum supply current Bipolar current-mode control integrated circuits require five times more operating current. dual totem-pole CMOS outputs drive power MOSFETs bipolar transistors. 50nsec typical output rise fall times (1000pF capacitive loads) minimize MOSFET power dissipation. Output peak current 300mA. TC170 contains full array system-protection circuits (see features). Current-mode control lets users parallel power supply modules. more TC170 controllers slaved together parallel operation. Circuits operate from master TC170 internal oscillator external system oscillator. TC170 operates from power supply. internal 5.1V reference minimizes external component count. TC170 compatible with Unitrode UC1846/2846/3846 bipolar controller. Other advantages inherent current-mode control include superior line load regulation automatic symmetry correction push-pull converters.
ORDERING INFORMATION
Part TC170COE TC170CPE Package Temperature Range
16-Pin SOIC (Wide) +70°C 16-Pin Plastic (Narrow) +70°C
FUNCTIONAL BLOCK DIAGRAM
VREF SYNC CURRENT SENSE INPUT CURRENT SENSE INPUT COMP ERROR INPUT ERROR INPUT 5.1-VOLT REFERENCE TC170 ERROR AMPLIFIER 350mV LOCK-UP AMPLIFIER POSITIVE FEEDBACK 3.5k 100µA 3.15 CURRENT AMPLIFIER 0.75V COMPARATOR LIMIT BUFFER AMPLIFIER SHUTDOWN COMPARATOR SHUTDOWN LATCH OSCILLATOR UNDERVOLTAGE LOCKOUT OUTPUT GROUND
OUTPUT
CURRENT LIMIT/ SOFT-START ADJUST
NOTE: Outputs state.
TC170-5 10/1/96 TelCom Semiconductor reserves right make changes circuitry specifications devices.
CMOS CURRENT MODE CONTROLLER TC170
ABSOLUTE MAXIMUM RATINGS*
Supply Voltage .18V Output Voltage Analog Inputs 0.3V 0.3V Storage Temperature Range 65°C +150°C Lead Temperature (Soldering, sec) +300°C Maximum Chip Temperature 150°C Plastic Package Thermal Resistance: (Junction Ambient) 140°C/W (Junction Case) 70°C/W Operating Temperature Range Commercial +70°C
*Static-sensitive device. Unused devices must stored conductive material. Protect devices from static discharge static fields. Stresses above those listed under Absolute Maximum Ratings cause permanent damage device. These stress ratings only functional operation device these other conditions above those indicated operational sections specifications implied. Exposure Absolute Maximum Rating Conditions extended periods affect device reliability.
ELECTRICAL CHARACTERISTICS: 16V, 24k, 1nF, 25°C, unless otherwise indicated.
Symbol
VREF
Parameter
Output Voltage Line Regulation Load Regulation Temperature Coefficient Oscillator Frequency Voltage Stability Temperature Stability
Test Conditions
IOUT IOUT 10mA Over Operating Temperature Range
Unit
mV/°C
Reference Voltage
VRTC
Oscillator
Over Operating Temperature Range
Error Amplifier
VCMRR AVOL CMRR PSRR Input Offset Voltage Input Bias Current Common-Mode Input Voltage Open-Loop Voltage Gain Unity Gain Bandwidth Common-Mode Rejection Ratio Power Supply Rejection Ratio Amplifier Gain Maximum Differential Input Signal Common-Mode Input Voltage
VOUT VCMV 1.1V VPIN4 VPIN3
3.15
Current Sense Amplifier
0.35
Current Limit Adjust
Current Limit Offset Voltage Input Bias Current Threshold Voltage Input Voltage Range Minimum Latching Current Maximum Nonlatching Current Output Voltage Output Level Output Level Output High Level ISINK 20mA ISINK 100mA ISOURCE 20mA
Shutdown Terminal
Output Stage
CMOS CURRENT MODE CONTROLLER TC170
ELECTRICAL CHARACTERISTICS: 16V, 24k, 1nF, 25°C, unless otherwise indicated.
Symbol
Parameter
Output High Level Output Rise Time Output Fall Time Start-Up Threshold Hysteresis
Test Conditions
ISOURCE 100mA 1000pF 1000pF Threshold
Unit
nsec nsec
Output Stage (Cont.)
7.15 0.75 8.25
Undervoltage Lockout
Supply
Standby Supply Current
DESCRIPTION
Symbol (16-Pin Plastic DIP) Package
SOFT START/ILIM VREF ISENSE ISENSE ERROR ERROR CMPTR SYNC OUTPUT OUTPUT SHDN
Description
Soft Start Adjust Current Limit. setting peak current threshold sense inputs (pins Second function this Soft-Start Adjust. Reference supply output volts. supply minimum 10mA. Current Sense Input. Inverting input sensing peak current pass transistor through series sense current monitor resistor. Current Sense Input. Non-inverting input used conjunction with This senses positive current monitor resistor. Error Non-inverting input output voltage regulation. Error Inverting input amplifier reference voltage. compensation feedback loop response. Timing capacitor (CO) input oscillator frequency conjunction with resistor input. Second function setting crossover dead time 11and outputs. Timing resistor (RO) input oscillator frequency setting constant current charge rate charge capacitor controller oscillator synchronization more controllers. clock input sync oscillator from external signal. output drive phase from push pull transistors. Ground return input output pins. Supplies power operate output drivers only. Output phase from push pull transistors. Voltage bias supply TC170 circuits except output transistors. Input disable both output drives OFF.
CONFIGURATIONS (DIP SOIC)
SOFT START/ ILIM VREFOUT SENSE SENSE ERROR ERROR CMPTR SHDN OUTPUT OUTPUT SYNC CINT ACOM CREF CREF VREF
DIGITAL CMPTR
TC170
TC170COE
VREF
NOTE: Outputs "OFF" state.
CMOS CURRENT MODE CONTROLLER TC170
Peak Current Limit Setup
Resistors current limit input (pin TC170 peak current limit (Figure potential easily calculated: VREF input pulse should least 500nsec wide have amplitude least order minimum propagation delay from input output. these parameters met, delay should less than 600nsec 25°C; however, delay time will increase device temperature rises.
Soft Restart From Shutdown
soft restart programmed nonlatched shutdown operation used. capacitor will cause gradual increase potential toward When voltage reaches 0.75V, latch input removed circuit establishes regulated output voltage. soft-start operation forces output drivers initially operate with minimum duty cycle peak currents. Even soft start required, necessary insert capacitor between ground current greater than 125µA. This capacitor will prevent "noise triggering" latch, minimize soft-start effect.
should selected first. shutdown circuit feature latched (VREF 0.35)/R1 50µA latched currents greater than 125µA. error amplifier output voltage clamped from going above through limit buffer amplifier. Peak current sensed amplified current amplifier which fixed gain 3.15. IPCL, peak current limit, current that causes comparator noninverting input exceed potential inverting input. Once comparator trip point exceeded, both outputs disabled. IPCL easily calculated: IPCL where: VREF 0.75V 3.15 (RS)
Soft-Start Power-Up
During power-up, capacitor initiates softstart cycle. input voltage (pin exceeds undervoltage lockout potential (7.7V), turned OFF, ending undervoltage lockout. Whenever comparator inverting input below 0.5V, both outputs disabled. When undervoltage lockout level passed, capacitor begins charge. duty cycle increases until operating output voltage reached. Soft-start operation forces output drivers initially operate with minimum duty cycle peak current.
VREF Internal voltage reference 5.1V 3.15 Gain current-sense amplifier 0.75V Current limit offset Both driver outputs (pins (LOW) when peak current limit exceeded. When sensed current goes below IPCL, circuit operates normally.
Output Shutdown
TC170 outputs turned quickly through shutdown input (pin 16). signal greater than forces shutdown comparator output HIGH. latch held set, disabling outputs. also turned VREF/R1 greater than 125µA, positive feedback through lockup amplifier keeps inverting comparator inverting input below 0.75V. remains even after shutdown input signal removed, because positive feedback. state cleared only through power-up cycle. Outputs will disabled whenever potential below 0.75V. shutdown terminal gives fast, direct disable TC170 output transistors. System protection remote shutdown applications possible.
Current-Sense Amplifier
current-sense amplifier operates fixed gain 3.15. Maximum differential input voltage (VPIN4 VPIN3) 1.1V. Common-mode input voltage range Resistive-sensing methods shown Figure Figure 2(A), simple filter limits transient voltage spikes caused external output transistor-collector capacitance. Transformer coupling (Figure offers isolation better power efficiency, cost complexity increase. order minimize propagation delay from input current amplifier output terminals, current ramp should order 1µsec width (min). Typical time delay values 400nsec region 25°C. delay time increases with device temperature that 50°C, delay times increased much 100nsec.
CMOS CURRENT MODE CONTROLLER TC170
SWITCH CURRENT 3.15 CURRENT-SENSE AMPLIFIER ERROR AMPLIFIER LIMIT BUFFER AMPLIFIER COMPARATOR FROM UNDERVOLTAGE LOCKOUT LATCH 5.1V VREF
OUTPUT (LOW)
0.75V
350mV
LOCK-UP AMPLIFIER POSITIVE FEEDBACK
SHUTDOWN COMPARATOR
350mV TC170 3.5k
Figure
Maximum Peak Output Current
3.15 CURRENTSENSE AMPLIFIER
VOUT
3.15 CURRENTSENSE AMPLIFIER TC170
*OPTIONAL FILTER
TC170
Ground Reference
Above-Ground Resistive Sensing
Figure
Resistive Sensing
CMOS CURRENT MODE CONTROLLER TC170
3.15 CURRENT- SENSE AMPLIFIER TC170
TC170
MASTER
SYNC
CMPTR
TC4427
Figure Transformer Isolated Current Sense
Undervoltage Lockout
undervoltage lockout circuit forces TC170 outputs (low) supply voltage below 7.7V. Threshold hysteresis 0.75V guarantees clean, jitter-free turn-on turnoff points. hysteresis also reduces capacitive filtering requirements controller supply input (pin 15).
SLAVE VREF SYNC CMPTR
TC170
Circuit Synchronization
Current-mode-controlled power supplies operated parallel with common load. Paralleled converters will equally share load current. Voltage-mode controllers unequally share load current, decreasing system reliability. more TC170 controllers slaved together parallel operation. Circuits operate from master TC170 internal oscillator with external driver (Figure Devices also slaved external oscillator (Figure Disable internal slave device oscillators grounding Slave controllers derive oscillator from bidirectional synchronization output signal bidirectional that intended both sync output input. This accomplished making output driver "weak." This advantageous that eliminates additional from package does enable device directly drive another device. order make effective driver, buffer required (Figure order sync input, necessary overcome internal driver. This requires pulse with amplitude equal VIN. Since must above 8.25V undervoltage lockout disabled, CMOS opencollector driver should used.
Figure
Master/Slave Parallel Operation
EXTERNAL* OSCILLATOR
TC4427
SYNC TC170 VREF SYNC TC170 VREF
*PULSE WIDTH OSCILLATOR
Figure
External Clock Synchronization
CMOS CURRENT MODE CONTROLLER TC170
2.3V 4.3V
ICHARGE
2.3V
2.3V
ON-TIME
SYNC DISCHARGE CURRENT
OUTPUT DEAD TIME (TD)
Figure Oscillator Circuit
Oscillator Frequency Output Dead Time
oscillator frequency 1000pF
OSCILLATOR RESISTANCE
500pF 1000pF 750pF OSCILLATOR FREQUENCY (kHz) 250pF +25°C
1.27 2800 ROCO RO2CO
10-12
where: Oscillator Resistor Oscillator Capacitor Oscillator Frequency (Hz) oscillator resistor range from 50k. Oscillator capacitor range from 250pF 1000pF. Figure shows typical operation various resistance capacitance values. During transitions between outputs, simultaneous conduction prevented. Oscillator fall time controls output off, dead time (Figure Dead time approximately: 2000 [CO]
Figure
Oscillator Frequency Oscillator Resistance
where: Oscillator Resistor Oscillator Capacitor (pF) Output Dead Time (sec) Maximum possible duty cycle dead time.
CMOS CURRENT MODE CONTROLLER TC170
TYPICAL CHARACTERISTICS
Output Rise Fall Times
+25°C CLOAD 500pF
Output Rise Fall Times
+25°C CLOAD 1800pF
Output Rise Fall Times
+25°C CLOAD 1000pF
50nsec
nsec 50nsec
PACKAGE DIMENSIONS 16-Pin Plastic (Narrow)
.260 (6.60) .240 (6.10)
.770 (19.56) .745 (18.92) .200 (5.08) .140 (3.56) .150 (3.81) .115 (2.92)
.310 (.787) .290 (.737)
.040 (1.02) .020 (0.51)
.015 (0.38) .008 (0.20) .400 (10.16) .310 (7.87)
MIN.
.110 (2.79) .090 (2.29)
.070 (1.78) .045 (1.14)
.022 (0.56) .015 (0.38)
CMOS CURRENT MODE CONTROLLER TC170
PACKAGE DIMENSIONS (Cont.) 16-Pin SOIC (Wide)
.299 (7.59) .419 (10.65) .290 (7.40) .394 (10.10)
.413 (10.49) .398 (10.10) .104 (2.64) .097 (2.46) .050 (1.27) TYP. .019 (0.48) .014 (0.36) .012 (0.30) .004 (0.10)
MAX. .050 (1.27) .015 (0.40)
.013 (0.33) .009 (0.23)
Dimensions: inches (mm)
Sales Offices
TelCom Semiconductor 1300 Terra Bella Avenue P.O. 7267 Mountain View, 94039-7267 TEL: 650-968-9241 FAX: 650-967-1590 E-Mail: liter@c2smtp.telcom-semi.com TelCom Semiconductor Austin Product Center 9101 Burnet Suite Austin, 78758 TEL: 512-873-7100 FAX: 512-873-8236 TelCom Semiconductor H.K. Ltd. Chuk Street, Ground Floor Kong, Kowloon Hong Kong TEL: 852-2324-0122 FAX: 852-2354-9957
Printed U.S.A

TC170 TC170 CMOS CURRENT MODE CONTROLLER Supply Current With CMOS

Top Searches for this datasheet

Other recent searches