LB11923V-TLM-E 查看數據表（PDF） - ON Semiconductor

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LB11923V-TLM-E

Three-Phase Brushless Motor Driver

ON Semiconductor 

LB11923V

stop or brake state, or the power must be turned off

and reapplied.

12. Low-voltage Protection Circuit:

The LB11923V includes a low-voltage protection

circuit to protect against incorrect operation when

power is first applied or if the power-supply

voltage (VCC) falls. The (external) all output

transistors are turned off if VCC falls under about

3.75 V, and this function is cleared at about 4.0 V.

13. Power Supply Stabilization:

Since this IC is used in applications that draw

large output currents, the power-supply line is

subject to fluctuations. Therefore, capacitors with

capacitances adequate to stabilize the

power-supply voltage must be connected between

the VCC pin and ground. If diodes are inserted in

the power-supply line to prevent IC destruction

due to reverse power supply connection, since this

makes the power-supply voltage even more subject

to fluctuations, even larger capacitors will be

required.

14. Ground Lines:

The signal system ground and the output system

ground must be separated and a single ground

point must be taken at the connector. Since the

output system ground carries large currents, this

ground line must be made as short as possible.

• Output system ground ... Ground for Rf and the

output diodes

• Signal system ground ... Ground for the IC and

the IC external components

15. VREG Pin:

If a motor drive system is formed from a single

power supply, the VREG pin (pin 1) can be used to

create the power-supply voltage (about 6.3 V) for

this IC. The VREG pin is a shunt regulator and

generates a voltage of about 7 volts by passing

a current through an external resistor. A stable

voltage can be generated by setting the current to

value in the range 0.2 to 1.5 mA. The external

transistors must have current capacities of at least

80 mA (to cover the ICC + Hall bias current +

output current <source> requirements) and they

must have voltage handling capacities in excess of

the motor power−supply voltage. Since the heat

generated by these transistor may be a problem,

heat sinks may be required depending on the

packages used. If the IC power-supply voltage

(4.4 to 7.0 V) is provided from an external circuit,

apply that voltage directly to the VCC pin (pin 37

and pin 38). In that case, the VREG pin must either

be left open or connected to ground.

16. FG Amplifier:

The FG amplifier is normally implemented as

a filter amplifier such as that shown in the

application circuits to reject noise. Since a clamp

circuit has been added at the FG amplifier output,

the output amplitude is clamped at about 3 V p-p,

even if the gain is increased.

Since a Schmitt comparator is inserted after the

FG amplifier, applications must set the gain so that

the amplifier output amplitude is at least

250 mV p-p. (It is desirable that the gain be set so

that the amplitude is over 0.5 V p-p at the lowest

controlled speed to be used.)

The capacitor inserted between the FGIN+ pin

(pin 23) and ground is required for bias voltage

stabilization. To make the connected capacitor as

immune from noise as possible, connect this

capacitor to the GND pin (pin 29 and pin 30) with

a line that is as short as possible.

17. Integrating Amplifier:

The integrating amplifier integrates the speed error

pulses and the phase error pulses and converts

them to a speed command voltage. At the same

time it also sets the control loop gain and

frequency characteristics using external

components.

The integrating amplifier output (pin 15) is

normally connected to the TOC pin (pin 16) using

external wiring. In cases where it is necessary to

switch the integration constant in an application

that uses a wide speed range by isolating the

integrating amplifier output and the PWM control

circuit, this type of constant switching application

can be implemented by adding external

operational amplifier, analog switch, and other

components.

In either case, the basic idea is that the operational

amplifier output is connected to the TOC pin.

(Note that voltages in excess of VCC – 0.5 V must

not be applied to the TOC pin.)

18. FIL Pin External Components:

The capacitor inserted between the FIL pin and

ground is used to suppress ripple on the FIL pin

voltage. Therefore, application designers must

select a capacitance value that provides fully

adequate smoothing of the FIL pin voltage even at

the lowest external clock input frequency used.

Also, the FIL pin voltage convergence time (the

time until the reference signal stabilizes) when the

input clock frequency is switched is shortened by

connecting a resistor and a capacitor in series

between the FIL pin and ground. Therefore,

designers must select values for the resistor and

capacitor that give the required convergence time.

19. R and C Pin External Components:

The maximum range over which the reference

signal frequency fVCO can be varied when 5 V is

used as the VCC supply voltage is about a factor of

three.

When it is desirable to make this range as wide as

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