Monolithic Digital LB1921 Three-Phase Brushless Motor Driver

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Monolithic Digital LB1921 Three-Phase Brushless Motor Driver

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Ordering number EN5439
Monolithic Digital
LB1921
Three-Phase Brushless Motor Driver Applications
Overview
LB1921 single-chip motor driver circuit that provides direct drive output appropriate driving power brushless motors used office automation equipment. LB1921 also provides variety peripheral functions, including speed control amplifier circuits, chip.
Package Dimensions
unit: 3147A-DIP28HS
[LB1921]
Applications
Paper feed drum motor drivers units
Functions Features
LB1921 improved output current version LB1824. Three-phase bipolar brushless motor driver Digital speed control circuit Thermal shutdown circuit Start/stop Lock detector output Crystal oscillator divider circuits error amplifiers Power supply current limiter
SANYO: DIP28HS
SANYO Electric Co.,Ltd. Semiconductor Bussiness Headquarters
TOKYO OFFICE Tokyo Bldg., 1-10, Chome, Ueno, Taito-ku, TOKYO, JAPAN
53096HA (OT) 5439-1/10
LB1921
Specifications
Absolute Maximum Ratings 25°C
Parameter Maximum supply voltage Maximum supply voltage Output current Allowable power dissipation Allowable power dissipation Operating temperature Storage temperature Symbol max1 max2 Topr Tstg Independent With arbitrarily large heat sink Conditions Ratings +150 Unit
Allowable Operating Ranges 25°C
Parameter Power supply voltage range Power supply voltage range Schmitt output applied voltage Fixed voltage output current Fixed voltage output current Fixed voltage output current Schmitt output current Lock detector output current Symbol VFGS IFGS output output output Conditions Ratings Unit
Electrical Characteristics 25°C,
Parameter Current drain Current drain Output saturation voltage Output saturation voltage Output leakage current [7-V Fixed Voltage Output] Output voltage Voltage variation Load variation [5-V Fixed Voltage Output] Output voltage Voltage variation Load variation [4-V Fixed Voltage Output] Output voltage Voltage variation Load variation [Hall Amplifier] Input bias current Common mode input voltage range Hall input sensitivity Hysteresis Input voltage high Input voltage high [Oscillator] Output high-level voltage Output low-level voltage Oscillator frequency Amplitude (CR) (CR) f(CR) V(CR) 1000 Vp-p VSLH VSHL VICM mVp-p VFG1 VFG2 3.65 4.35 4.45 4.80 5.15 6.65 7.35 Symbol ICC1 ICC2 (sat)1 (sat)2 leak Stop mode Conditions Ratings Unit
Continued next page.
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LB1921
Continued from preceding page.
Parameter [Current Limiter Operation] Limiter [Thermal Shutdown Operation] Thermal shutdown operating temperature Hysteresis Amplifier] Input offset voltage Input bias current Output high-level voltage Output low-level voltage input sensitivity Schmitt width next stage Operating frequency range Open-loop gain [FGS Output] Output saturation voltage Output leakage current [Speed Discriminator] Output high-level voltage Output low-level voltage [PLL Output] Output high-level voltage Output low-level voltage [Counts] [Lock Detector] Output low-level voltage Lock range [Integrator] Input bias current Output high-level voltage Output low-level voltage Open-loop gain Gain-bandwidth product Reference voltage [Crystal Oscillator] Operating frequency range [Start/Stop Pin] Input high-level voltage Input low-level voltage Pull-down resistor [Reversing Pin] Input high-level voltage Input low-level voltage Hysteresis Pull-down resistor (F/R) (F/R) (F/R) (S/S) (S/S) (S/S) fOSC (INT) (INT) (INT) VX/2 -0.4 +0.4 (LD) 0.15 6.25 (FGS) (FGS) (FGS f(FG) (FG) (FG) (FG) (FG) Gain: Design target value VCC-VM Symbol Conditions Ratings Unit
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LB1921 Assignment
Functions
Symbol FGIN+ FGIN- FGOUT OUT1 OUT2 OUT3 GND2 power supply power supply Power supply blocks other than output block pulse input (4-V power supply) pulse input amplifier output oscillator frequency setting Output Output Output Output block ground Forward/reverse control Low: forward, high: reverse Start/stop control Low: start, high: stop Used both power supply output block output current detection. output current converted voltage detected inserting resistor between this VCC. Hall input OUT1 Hall input OUT2 Hall input OUT3 Crystal oscillator connection. Connect crystal oscillator element this pin. Ground blocks other than output block Lock detector This goes when motor speed within lock range (±6.25%). Speed discriminator output Over speed high Integrator input Integrator output (speed control) output amplifier output (after Schmitt trigger circuit) Function
IN1+, IN1- IN2+, IN2- IN3+, IN3- Xtal GND1
DOUT INTIN INTOUT POUT FGSOUT
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LB1921 Truth Table
Source Sink OUT3 OUT2 OUT3 OUT1 OUT2 OUT1 OUT2 OUT3 OUT1 OUT3 OUT1 OUT2 high
Note: Input high refers state where IN-.
formula below gives relationship between oscillator frequency (fOSC) frequency (fFC). (servo) fOSC/(ECL divisor (16) number counts) fOSC/8192 Crystal Oscillator External Circuit External Circuit Constants (reference values)
Xtal (MHz) (pF) (pF) 0.82
Note: crystal used must have fundamental frequency impedance impedance ratio greater.
Equivalent Circuit Block Diagram
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LB1921 Sample Application Circuit
Test Circuit Diagram
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LB1921 This section describes LB1921 external components used. Speed Control Circuit This uses combination speed discriminator circuit circuit speed control. speed discriminator circuit outputs error signal once every periods using charge pump technique. circuit outputs phase error signal once every period, also using charge pump technique. compared earlier schemes that only used speed discriminator, combination circuit with speed discriminator provides improved speed variation suppression when using motor with large load variations. Since following formula determines servo frequency, motor speed must using number pulses crystal oscillator frequency. (servo) fOSC/8192 fOSC: crystal oscillator frequency Direct Drive This adopts direct drive minimize power loss output. output transistors always saturated when motor drive power adjusted changing output duty. Since output switching performed lower side transistor, three Schottky diodes must inserted between VCC. (Note that through current will flow instant lower side transistor turns these diodes have short reverse recovery time.) Normal rectifying diodes used diodes between ground. Current Control Circuit current control circuit applies current control current determined relation 0.5/Rf, i.e. peak current limitation. control operation reduces output duty thus suppresses current. phase compensation capacitor required. Speed Lock Range speed lock range ±6.25% fixed speed goes when motor lock range. (This open-collector output.) When motor speed goes lock range, LB1921 changes motor drive output duty according speed error control motor speed within lock range. Frequency frequency determined resistor capacitor connected pin. When connected fixed voltage supply fPWM 1/(1.2 When connected fixed voltage supply fPWM 1/(0.5 should smaller than frequency about desirable. frequency motor will vibrate frequency when motor restrained causing disturbing audible noise. Inversely, switching loss increases frequency high. Ground Leading GND1 (pin ground circuits other than output block. GND2 (pin ground output block (emitters sink transistors). connected GND2. other external components connected GND1. GND1 GND2 lines connected single ground point connector. Since GND2 carries large currents, should kept short possible. Output Parasitic Effects Parasitic effects occur when output voltage falls -0.7 (this value decreases temperature increases) below GND1 GND2 voltage. Similarly, output voltage should allowed exceed more than When parasitism occurs, initially speed control lost intermittently, amount parasitism increases output transistors destroyed. Schottky diodes with small used prevent through currents. result, potential difference between output pins that much problem. Although normal rectifying diodes used printed circuit board pattern must kept short possible recommended item prevent parasitism from occurring.
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LB1921 External Interface Pins Output type: Open collector Breakdown voltage: Maximum supply voltage Saturation voltage sample-to-sample variation (reference value) (ILD 0.10 0.15 Output type: Open collector Breakdown voltage: Maximum supply voltage Saturation voltage sample-to-sample variation (reference value) (IFGS 0.12 0.18 outputs amplifier output converted pulse output hysteresis comparator speed monitoring. pull-up resistor required when this used. Start/stop Input type: transistor base with 50-k pull-down resistor ground. Threshold level (typical): about stop mode, 4-V, 5-V, fixed voltage power supplies turned off. Input type: transistor base with 50-k pull-down resistor ground. Threshold level (typical): about (high low), about (low high) Hysteresis: about switching must done when stopped. Fixed Voltage Power Supply Temperature Characteristics power supply: about -0.5 mV/°C (typical) power supply: about -0.6 mV/°C (typical) power supply: about -2.5 mV/°C (typical) Amplifier resistors amplifier gain, with gain being determined formula R2/R1. capacitors determine amplifier frequency characteristics, with forming high-pass filter forming low-pass filter. Since amplifier followed Schmitt comparator, values must that amplifier output over mVp-p. particular, desirable that amplifier output between during steady-state rotation. External Capacitors capacitor required FGIN+ fixed voltage power supply stabilization internal logic initial reset pulse generation. Although value this capacitor quite small power supply stabilization, relatively large capacitance (about required reset pulse generation. reset pulse generated during time FGIN+ goes from about reset does operate, will turn briefly startup. this phenomenon problem, capacitor about used After charged when turned motor stopped), charge discharged through internal resistance ground, which about capacitors required fixed voltage power supply stabilization. Since this adopts direct drive scheme switches large currents output, noise occur easily. Thus power supply must adequately stabilized that this noise does cause operate incorrectly. must connected close possible GND1. particular, C1's characteristics easily influenced thus require caution.
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LB1921 External Resistors resistors exist apply high-level input pin. Since input pull-down resistor about level when open. Apply voltage over under input high level. resistor exists apply high-level input pin. Since input pull-down resistor about level when open. Apply voltage over under start state high level input. Although dividing voltage with resistors, done with input, would improve resistance noise since lower input impedance when noise problem high level connecting single resistor such R15. value recommended. rises slowly (less than about V/ms) when power first applied, motor rotate somewhat stop mode). This because input voltage resistor divided input voltage will under (the start input level) when under rise rate cannot increased this phenomenon problem, resolved connecting capacitor between pin. Through Currents Direct Scheme direct scheme, through currents flow outputs transistor switching applications implemented with either discrete components LB1822. This output transistor delays parasitic capacitances. Previously, when this problem, additional capacitors were used resolve problem. However, since LB1921 resolves this problem circuit level, additional external components required. During switching, whiskers less than about observed voltage waveform, these problem. Oscillator Element Normally, crystal oscillator used with this speed control characteristic requirements stringent, ceramic oscillator could used. avoid problems, consult manufacturer oscillator element when selecting oscillator element determining values external resistors capacitors. Sample Internal Power Dissipation Calculation (calculated typical rated values) Power dissipation current drain (ICC) Start mode: ICC1 0.82 Stop mode: ICC2 0.19 Power dissipation when drawn from fixed voltage power supply (VCC 0.17 Power dissipation output drive current (when output duty 100%) {(VCC 1)2/8 {(VCC 2)2/10 (232/8 (222/10 0.12 Power dissipation output drive transistors (when output duty 100%) sat2 Therefore, total power dissipation whole stop mode: 0.19 start mode: 6.51 (For output duty 100%) Temperature Rise Measurement Techniques Thermocouple measurement Attach thermocouple heat sink when using thermocouple measure temperature. This technique simple subject large measurement errors when heat generation consistent. Measurement using internal diode characteristics recommend using parasitic diode that exists between INT.IN ground this (According Sanyo data, temperature characteristic this diode about V/°C mA.) external resistor must removed during testing.
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LB1921 Servo Constants Since servo constant calculation depends strongly motor characters requires significant expertise, recommend that motor manufacturer determine constants normal cases. Sanyo provide required characteristics data servo constant calculations frequency characteristics simulation data filter characteristics specified motor manufacturer. When resistor (R10) inserted between DOUT INT.IN small, will become large large speed errors become more likely occur speed discriminator cutoff integrator input current. Therefore, value between advisable. resistor (R8) inserted between POUT INT.IN small, influence system will large pull-in synchronization with lock state will degrade. Therefore, this resistor must small. recommend value around when First determine constants speed discriminator (R9, R10, then determine value system.
products described contained herein intended surgical implants, life-support systems, aerospace equipment, nuclear power control systems, vehicles, disaster/crime-prevention equipment like, failure which directly indirectly cause injury, death property loss. Anyone purchasing products described contained herein above-mentioned shall: Accept full responsibility indemnify defend SANYO ELECTRIC CO., LTD., affiliates, subsidiaries distributors their officers employees, jointly severally, against claims litigation damages, cost expenses associated with such use: impose responsibility fault negligence which cited such claim litigation SANYO ELECTRIC CO., LTD., affiliates, subsidiaries distributors their officers employees jointly severally. Information (including circuit diagrams circuit parameters) herein example only; guaranteed volume production. SANYO believes information herein accurate reliable, guarantees made implied regarding infringements intellectual property rights other rights third parties. This catalog provides information December, 1997. Specifications information herein subject change without notice. 5439-10/10

Monolithic Digital LB1921 Three-Phase Brushless Motor Driver

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