LB1821 Sanyo, LB1821 Datasheet
LB1821
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LB1821 Summary of contents
Page 1
... A motor drive circuit with the desired output capability (voltage and current characteristics) can be constructed by attaching a driver array at the IC output. The LB1821M includes on chip a speed control circuit that allows the motor speed to be varied using an external clock. ...
Page 2
... Input voltage high low [RC Oscillator] Output high-level voltage Output low-level voltage Oscillator frequency Amplitude [CROCK Oscillator] Output high-level voltage Output low-level voltage External capacitor charge current External capacitor discharge current Oscillator frequency Amplitude LB1821M = 6 Symbol Conditions stop mode ...
Page 3
... Input offset voltage Input bias current Output high-level voltage Output low-level voltage Open-loop gain Input bias current Gain-bandwidth product Reference voltage [Filter Amplifier] Input bias current Output high-level voltage Output low-level voltage Reference voltage LB1821M Symbol Conditions V 1 OH( OH( ...
Page 4
... Input low-level voltage Hysteresis Pull-up resistance [Low Voltage Protection] Operating voltage Release voltage Hysteresis Speed Discriminator Counts N1 N2 Number of counts High or open High or open High or open L 256 L High or open 128 L L 512 LB1821M Symbol Conditions V OH(S/S) V OL(S/S) ∆V 1 IN(S/S) ∆ IN(S/ U(S/S) V IH(F/R) V IL(F/R) ∆V ...
Page 5
... S/S Pin High or open Stop L Start Pin Assignment LB1821M Output IN2 IN3 Source Sink BRK Pin ...
Page 6
... Sample Application Circuit LB1821M No. 5686-6/16 ...
Page 7
... Internal Equivalent Circuit Block Diagram LB1821M No. 5686-7/16 ...
Page 8
... The FG servo frequency is controlled to be the same frequency as the clock signal input to the CLK pin. This means that the motor speed can be changed by changing the clock frequency. 2. VCO Circuit The LB1821M includes an on-chip VCO circuit to generate the reference signal for the speed discriminator circuit. The reference signal frequency is determined by the following formula. f ...
Page 9
... C (µF) To release the constraint protection state, the LB1821M must be set to either the stop state or the brake state, or power must be reapplied. The CROCK pin must be connected to ground if the constraint protection circuit is not used ...
Page 10
... If the motor is started and stopped repeatedly over a short period, the charge accumulated on the integrating amplifier’s external capacitor may become a problem. (This can result in abnormal speed overshooting at startup and other problems.) The circuit shown below can be effective at resolving this problem. LB1821M and the output diodes f ...
Page 11
... Speed control system PLL output P Outputs the phase comparison result for 4 OUT 1/2 f and 1 CLK FG Speed lock detection output Open collector output 5 LD Goes low when the motor speed is within the speed lock range (±6.25%). LB1821M Functions ) low Equivalent circuit Continued on next page. No. 5686-11/16 ...
Page 12
... An open state functions as a high-level input. Low for start, high or open for stop mode operation. The hysteresis is about 0.45 V. Speed discriminator count switching Low 1 High: 4 open state functions as a high-level input. The hysteresis is about 0.45 V. LB1821M Functions Equivalent circuit Continued on next page. No. 5686-12/16 ...
Page 13
... An initial reset is applied to the logic circuit block connecting an external capacitor (of about 0.1 µF) between the FGIN+ pin and ground Ground connections GND These pins are all connected internally to the frame. LB1821M Functions FG Schmitt comparator FG reset circuit potential) CC Equivalent circuit Continued on next page. No. 5686-13/16 ...
Page 14
... These are open collector sink outputs Outputs (Fixed current source outputs Power-supply voltage V 32 Connect a capacitor between this pin and ground for power CC supply stabilization. LB1821M Functions + > IN – , and low as the opposite set to be OUT Equivalent circuit Continued on next page. No. 5686-14/16 ...
Page 15
... VCO oscillator connection. This pin sets the VCO frequency Connect a capacitor between this pin and ground. Set the value of the capacitor so that the oscillator frequency does not exceed 1 MHz. LB1821M Functions Equivalent circuit Continued on next page. No. 5686-15/16 ...
Page 16
... 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. LB1821M Functions pin. .OUT ...