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Ordering number : EN5679
Monolithic Digital IC
LB1922
Three-Phase Brushless Motor Driver for Office Automation Applications
Overview
The LB1922 is a single-chip drive circuit that provides the direct PWM drive output appropriate for the power brushless motors used in office automation equipment. It provides a variety of peripheral circuits on chip, including
a speed control circuit and an FG amplifier. It is optimal in systems that use a 12-V power supply.
Package Dimensions
unit: mm 3147A-DIP28HS
[LB1922]
Allowable power dissipation, Pd max - W
With an arbitrarily large heat sink
Ambient temperature, Ta - C
SANYO: DIP28HS
Specifications
Absolute Maximum Ratings at Ta = 25C
Parameter Supply voltage Output current Allowable power dissipation Operating temperature Storage temperature Symbol VCC VM IO Pd max1 Pd max2 Topr Tstg T 100 ms Independent IC With an arbitrarily large heat sink Conditions Ratings 20 20 3.1 3 20 -20 to +80 -55 to +150 Unit V V A W W C C
Allowable Operating Ranges at Ta = 25C
Parameter Supply voltage range FG Schmitt output applied voltage Symbol VCC VM VFGS IO1 Fixed-voltage output current IO2 IO3 FG Schmitt output current Lock detection output current IFGS ILD 7 V output 5 V output 4 V output Conditions Ratings 9.5 to 18 9 to 18 0 to 8 0 to -20 0 to -20 0 to -15 0 to 5 0 to 20 Unit V V V mA mA mA mA mA
SANYO Electric Co.,Ltd. Semiconductor Bussiness Headquarters
TOKYO OFFICE Tokyo Bldg., 1-10, 1 Chome, Ueno, Taito-ku, TOKYO, 110 JAPAN
63097HA(OT) No. 5679-1/10
LB1922 Electrical Characteristics at Ta = 25C, VCC = VM = 12 V
Parameter Current drain 1 Current drain 2 Output saturation voltage 1 Output saturation voltage 2 Output leakage current [7-V Fixed-Voltage Output] Output voltage Line regulation Load regulation [5-V Fixed-Voltage Output] Output voltage Line regulation Load regulation [4-V Fixed-Voltage Output] Output voltage Line regulation Load regulation [Hall Amplifier] Input bias current Common-mode input voltage range Hall input sensitivity Hysteresis Input voltage (low high) Input voltage (high low) [Oscillator] Output high-level voltage Output low-level voltage Oscillator frequency Amplitude [Current Limiter Operation] Limiter [Thermal Shutdown Operation] Thermal shutdown operating temperature Hysteresis [FG Amplifier] Input offset voltage Input bias current Output high-level voltage Output low-level voltage FG input sensitivity Following stage Schmitt amplitude Operating frequency range Open-loop gain [FGS Output] Output saturation voltage 1 Output leakage current [Speed Discriminator] Output high-level voltage Output low-level voltage [PLL Output] Output high-level voltage Output low-level voltage [Number of Counts] VOH(P) VOL(P) 3.2 1.2 3.5 1.5 512 3.8 1.8 V V VOH(D) VOL(D) 4.0 4.3 0.8 1.1 V V VO(FGS) IL(FGS) IO(FGS) = 2 mA VO = 5 V 0.1 0.5 10 V A f(FG) = 2 kHz 45 51 VIO(FG) IB(FG) VOH(FG) VOL(FG) IFG = -2 mA IFG = 2 mA Gain: 100 x 3 100 180 250 2 -10 -1 5.5 6 1 1.5 +10 +1 mV A V V mV mV kHz dB TSD TSD Design target value 150 180 50 C C VCC-VM 0.4 0.5 0.6 V VOH(CR) VOL(CR) f(CR) V(CR) R = 56 k, C = 1000 pF 2.8 0.8 3.1 1.1 15 2.0 3.4 1.4 V V kHz Vp-p VIN VSLH VSHL IHB VICM -4 1.5 60 8 14 7 -7 24 -1 5.1 A V mVp-p mV mV mV VFG VFG1 VFG2 IO = -5 mA VCC = 9.5 to 18 V IO = -5 to -15 mA 3.65 4.0 40 110 4.35 200 200 V mV mV VX VX1 VX2 IO = -5 mA VCC = 9.5 to 18 V IO = -5 to -20 mA 4.45 4.80 50 5 5.15 200 200 V mV mV VH VH1 VH2 IO = -10 mA VCC = 9.5 to 18 V IO = -5 to -20 mA 6.65 7.0 50 40 7.35 200 200 V mV mV Symbol ICC1 ICC2 VO(sat)1 VO(sat)2 IOleak In stop mode IO = 1 A, VCC = VM = 10.5 V IO = 2 A, VCC = VM = 10.5 V Conditions Ratings min typ 34 8 2.0 2.7 max 50 11 3.0 4.2 100 Unit mA mA V V A
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No. 5679-2/10
LB1922
Continued from preceding page.
Parameter [Lock Detection] 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 resistance [Forward/Reverse Pin] Input high-level voltage Input low-level voltage Hysteresis Pull-down resistance VIH(F/R) VIL(F/R) VIN RD(F/R) 30 0.5 50 70 4.0 1.5 V V V k VIH(S/S) VIL(S/S) RD(S/S) 30 50 4.0 1.5 70 V V k fOSC 1 10 MHz -5% IB(INT) VOH(INT) VOL(INT) 60 1.6 VX/2 +5% -0.4 3.7 4.3 0.8 1.2 +0.4 A V V dB MHz V VOL(LD) ILD = 10 mA 0.15 6.25 0.5 V % Symbol Conditions Ratings min typ max Unit
Truth Table
Source sink 1 2 3 4 5 6 OUT2 OUT1 OUT3 OUT1 OUT3 OUT2 OUT1 OUT2 OUT1 OUT3 OUT2 OUT3 F/R=L IN1 H H H L L L IN2 L L H H H L IN3 H L L L H H IN1 L L L H H H F/R=H IN2 H H L L L H IN3 L H H H L L
Note: A high input is defined as IN+ > IN-.
Pin Assignment
No. 5679-3/10
LB1922 Pin Functions
Pin No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 20, 19 18, 17 16, 15 21 22 23 24 25 26 27 28 Pin 5V 7V VCC FGIN+ FGIN- FGOUT CR OUT1 OUT2 OUT3 GND2 F/R S/S VM IN1+, IN1- IN2+, IN2- IN3+, IN3- X'tal GND1 LD DOUT INTIN INTOUT POUT FGSOUT 5-V power supply. 7-V power supply Power supply for all blocks other than the output block FG pulse input (4-V power supply pin) FG pulse input FG amplifier output PWM oscillator frequency setting Output 1 Output 2 Output 3 Ground for the output block Forward/reverse control Forward: low, reverse: high Start/stop control Start: low, stop: high Output block power supply. This pin is also used for output current detection. The output current is converted to a voltage and detected by inserting a resistor (Rf) between this pin and VCC. Hall input for OUT1 Hall input for OUT2 Hall input for OUT3 Crystal oscillator. Connect a crystal oscillator to this pin. Ground for all circuits other than the output block. Lock detection Outputs a low level when the motor speed is within the lock range, i.e. within 6.25% of the set speed. Speed discriminator output Outputs a high level on overspeed. Integrator input Integrator output (speed control pin) PLL output FG amplifier output (After the Schmitt circuit) Function
The following formula gives the relationship between the crystal oscillator frequency (fOSC) and the FG frequency fFC. fFC (servo) = fOSC/(ECL divided by 16 times the number of counts) = fOSC/8192 External Crystal Oscillator Circuit
External Constants (Provided for reference only.)
Xtal (MHz) 3 to 4 4 to 5 5 to 7 7 to 10 C1 (pF) 39 39 39 39 C2 (pF) 82 82 47 27 R (k) 0.82 1.0 1.5 2.0
However, a crystal with a ratio between the impedance at the crystal fundamental frequency fo and the impedance at the third harmonic frequency (3fo) of at least 1:5 must be used.
No. 5679-4/10
LB1922 LB1922 Functional Description and Notes on External Components 1. Speed control circuit Speed control in this IC is implemented with the combination of a speed discriminator circuit and a PLL circuit. The speed discriminator circuit outputs an error output once every two FG periods using a charge pump technique. The PLL circuit outputs a phase error once every FG period, also using a charge pump technique. As compared to the earlier technique of only using a speed discriminator circuit, the combination of a speed discriminator circuit and a PLL circuit is better able to suppress speed fluctuations when used in situations where large load variations are applied to the motor. Since the FG servo frequency is determined by the following formula, applications must determine the motor speed by setting the number of FG pulses and the crystal oscillator frequency. fFG(servo) = fOSC/8192 fOSC: The crystal oscillator frequency 2. Direct PWM drive To minimize power loss in the output, this IC adopts a direct PWM drive technique. The output transistors are always saturated when on, and motor drive is adjusted by changing the duty with which the output transistors are on. Since the output switching is performed by the lower side transistors, Schottky diodes (D1, D2, and D3) or similar devices must be connected between OUT and VCC. (This is because if the devices used do not have a short reverse recovery time, through currents will flow at the instant the lower side transistors turn on.) Normal rectifying diodes can be used between OUT and ground. 3. Current limiter circuit The current limiter circuit operates at a current determined by the formula I = 0.5/Rf, and operates as a peak current limiter. Its current limiting operation consists of reducing the duty with which the output is on to suppress the current drawn. No phase compensation capacitors are required. 4. Speed lock range The speed lock range is 6.25% of the set speed. When the motor speed is in the lock range the LD pin goes low. (The LD pin is an open-collector output.) If the motor speed goes out of the lock range, the motor drive output on duty is modified according to the speed error. This controls the motor speed to be in the lock range. 5. PWM frequency The PWM frequency is determined by the resistor (R3) and the capacitor (C6) connected to the CR pin. * If R3 is connected to the 4-V fixed-voltage supply: fPWM 1/(1.2 x C x R) * If R3 is connected to the 7-V fixed-voltage supply: fPWM 1/(0.5 x C x R) Do not use a value of 30 k or less for R3. A PWM frequency of about 15 kHz is desirable. If the PWM frequency is too low, the motor may resonate at the PWM frequency during motor constraint, and if the PWM frequency is in the audible range result in noise. Inversely, if the PWM frequency is too high, the loss in the output transistors during switching will increase. 6. Ground leading GND1 (pin 22) --- Ground for all circuits other than the output block GND2 (pin 11) --- Output block ground (the sink transistor emitter) D4, D5, and D6 must be connected to GND2. All other external components must be connected to GND1. A single ground point must be taken for GND1 and GND2 at the connector. Since GND2 carries large currents, the GND2 lines must be kept as short as possible. 7. Parasitic effects in the output Parasitic effects occur when the output pin voltage falls -0.7 V below the GND1 and GND2 potential. (Note that the actual value may become smaller than -0.7 V due to device temperature characteristics.) Also, applications must be designed so that the output pin voltage never exceeds VCC by 1 V or more. If a parasitic effect occurs, at first speed control will be lost intermittently. If the parasitic effects increase, the output transistors may be destroyed. Since D1,
No. 5679-5/10
LB1922 D2, and D3 are for through current prevention, use Schottky diodes with a small Vf. This will prevent the potential difference between the output pins and VCC from becoming a problem. Although normal rectifying diodes can be used for D4, D5, and D6, design the ground lines carefully as described in item 6, "Ground leading", so that parasitic effects do not occur. 8. External interface pins * LD pin Output type: open collector Voltage handling capacity: 20 V (absolute maximum) Saturation voltage sample-to-sample variation reference value (ILD = 10 mA) 0.0 to 0.5 V * FGS pin Output type: open collector Voltage handling capacity: 20 V (absolute maximum) Saturation voltage sample-to-sample variation reference value (IFGS = 2 mA) 0.12 to 0.18 V The FGS pin output is the FG amplifier output converted to a pulse output by a hysteresis comparator. It is used as a speed monitor. If the FGS pin is not used, the pull-up resistor is not required. * Start/Stop pin Input type: PNP transistor base with a 50-k pull-down resistor connected to ground Threshold level (typical): About 2.6 V The 4-V, 5-V, and 7-V fixed-voltage supplies are turned off in stop mode. * F/R pin Input type: PNP transistor base with a 50-k pull-down resistor connected to ground Threshold level (typical): About 2.2 V (high low), about 2.7 V (low high) Hysteresis: about 0.5 V F/R switching must only be performed in stop mode when the motor is stopped. 9. Fixed-voltage supply temperature characteristics * 4-V supply: about -0.5 mV/C * 5-V supply: about -0.6 mV/C * 7-V supply: about -2.5 mV/C 10. FG amplifier The FG amplifier gain is determined by R1 and R2, and the DC gain, G, will be R2/21. The FG amplifier frequency characteristics are determined by C4 and C5. (R1 and C4 form a high-pass filter and R2 and C5 form a low-pass filter.) Since the FG amplifier output is input to a Schmitt comparator, set up values for R1, R2, C4, and C5 so that the FG amplifier output has an amplitude of at least 250 mV p-p. (It is desirable to set up the FG amplifier so that its output has an amplitude of between 1 and 3 V p-p during steady state motor operation.) 11. External capacitors * C3 C3 is required to stabilize the FGIN+ pin fixed-voltage supply and to generate the initial reset pulse for the IC internal logic. Although a relatively small capacitance suffices for power supply stabilization, a larger capacitance (about 4.7 F) is required to generate the reset pulse. The reset pulse is generated at the time when the FGIN+ pin goes from 0 V to about 1.3 V. If the reset function does not operate, the LD pin may go on briefly at startup. If this phenomenon is not a problem, a capacitance of around 0.1 F can be used for C3. After C3 is charged to 4 V, if VCC is turned off (or the IC is set to stop mode), the capacitor will be discharged by an IC-internal load of about 10 k that is connected to this capacitor. * C1 and C2 C1 and C2 are required for fixed-voltage supply stabilization. Since this IC adopts a direct PWM technique and switches large currents in the outputs, it is extremely easy for noise to be generated. Therefore, adequate powersupply stabilization is required to prevent that noise from causing incorrect circuit operation. C1 through C3 must be connected to GND1 with lines that are as short as possible. In particular, C1 can easily influence system characteristics and requires care.
No. 5679-6/10
LB1922 12. External resistors * R4 and R5 R4 and R5 are used to apply the high-level input to the F/R pin. Since the F/R pin has a built-in pull-down resistor which is about 50 k, it will be at the low level when left open. A voltage of between 4.0 and 6.3 V must be applied to input a high level to the F/R pin. * R15 R15 is used to apply the high-level input to the S/S pin. Since the S/S pin has a built-in pull-down resistor which is about 50 k, it will be at the low level when left open. (A voltage of between 4.0 and 6.3 V must be applied to input a start-state high level to the S/S pin.) As is the case with the F/R input, using a two-resistor voltage divider to apply a voltage to the S/S pin provides better noise immunity since a lower input impedance can be set up. However, in applications where noise is not a problem, the high level may be applied with a single resistor, as is done with R15 in this circuit. When VCC is first applied, if VCC comes up slowly (around 10 mV/ms or slower) the motor may turn somewhat even though the circuit is in stop mode. This is because the S/S pin input voltage is provided through a tworesistor voltage divider and when VCC is still relatively low, the S/S pin input voltage will be below 2.6 V, which is the start mode input level. If it is impossible to increase the speed with which the power voltage is brought up and this is a problem, a capacitor may be inserted between VCC and the S/S pin to resolve the problem. 13. Through currents due to the direct PWM technique In the direct PWM technique, through currents may flow in the output due to the switching. (This occurs in both discrete component implementations as well as with the LB1822.) This is due to the delay and parasitic capacitors in the output transistors. Earlier application used capacitors to deal with this problem if it occurred. However, since this IC includes circuits designed to deal with this phenomenon, there is no need for external components to deal with these currents. During switching, whiskers of up to about 10 ns may appear in the RF waveform, but they will not cause problems in applications. 14. Oscillators Normally, applications using this IC will use a crystal oscillator. However, it may be possible to use a ceramic oscillator in applications in which the requirements on the speed control characteristics are not demanding. To avoid problems, always consult the manufacturer of the oscillator element concerning the values of the external capacitors and resistors used. 15. IC internal power dissipation calculation (calculated for VCC = 12 V with typical specifications) * Power dissipation due to the supply current (ICC) Stop mode: P1 = VCC x ICC1 = 12 x 34 m = 0.41 W Start mode: P2 = VCC x ICC2 = 12 x 8 m = 0.08 W * Power dissipation when a -10-mA load current is drawn from the 7-V fixed voltage output. P3 = (VCC - 7) x 10 m = 5 x 10 m = 0.05 W * Power dissipation due to the output drive current (when the output duty is 100%) P4 = {(VCC -1)2/8k} + {(VCC - 2)2/10k} = (112/2k) + (102/4k) = 0.09 W * Power dissipation in the output transistors (when IO = 2 A, the output duty is 100%) P5 = VO (sat)2 x IO = 2.7 x 2 = 5.4 W Therefore, the IC overall power dissipation will be: Start mode: P = P2 = 0.08 W Stop mode: P = P1 + P3 + P4 + P5 = 5.95 W (For an output duty of 100%)
No. 5679-7/10
LB1922 16. Techniques for measuring IC internal temperature increases * Thermocouple measurement When using a thermocouple for temperature measurement, the thermocouple is attached to a fin on the heat sink. While this measurement technique is simple, it suffers from large measurement errors when the thermal generation process is not at steady state. * Measurement using IC internal diode properties We recommend using the properties of the parasitic diode that exists between INT.IN and ground for measuring the temperature of this IC. (Sanyo data: For ID = 1 mA, the temperature characteristic is about 1.8 mV/C.) The external resistor must be disconnected when measuring the temperature. 17. Servo constants The servo constant calculations depend strongly on the characteristics of the motor used and require special expertise. Normally, the motor manufacturer will set up these constants. Sanyo can provide the data required for the servo constant calculations. This data includes both the characteristics data for this IC as well as the frequency characteristics simulation data for the filter characteristics set up by the motor manufacturer. If the resistor (R10) between DOUT and INT.IN is too small, then C8 and C9 will become excessively large, and if R10 is too large, then speed errors due to the speed discriminator shutoff current and the integrator input current will become more likely to occur. Therefore, this resistor should have a value in the range 10 to 100 k. If the resistor (R8) between POUT and INT.IN is too small, the influence of the PLL system will become excessive and the lock state pull-in characteristics will be degraded. Thus the value of this resistor must not be made too small. We recommend a value of around 1 M when R10 is 75 k. Applications must be designed by first setting up only the speed discriminator system (R9, R10, C8, and C9) and only then setting up the PLL system resistor R8.
No. 5679-8/10
LB1922 Equivalent Circuit Block Diagram
Speed discriminator
2.5 V
No. 5679-9/10
LB1922 Sample Application Circuit
s No products described or contained herein are intended for use in surgical implants, life-support systems, aerospace equipment, nuclear power control systems, vehicles, disaster/crime-prevention equipment and the like, the failure of which may directly or indirectly cause injury, death or property loss. s Anyone purchasing any products described or contained herein for an above-mentioned use shall: Accept full responsibility and indemnify and defend SANYO ELECTRIC CO., LTD., its affiliates, subsidiaries and distributors and all their officers and employees, jointly and severally, against any and all claims and litigation and all damages, cost and expenses associated with such use: Not impose any responsibility for any fault or negligence which may be cited in any such claim or litigation on SANYO ELECTRIC CO., LTD., its affiliates, subsidiaries and distributors or any of their officers and employees jointly or severally. s Information (including circuit diagrams and circuit parameters) herein is for example only; it is not guaranteed for volume production. SANYO believes information herein is accurate and reliable, but no guarantees are made or implied regarding its use or any infringements of intellectual property rights or other rights of third parties. This catalog provides information as of June, 1997. Specifications and information herein are subject to change without notice. No. 5679-10/10

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