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

7. Hall Effect Sensor Input Signals:

An input amplitude of over 100 mV p-p is

desirable in the Hall effect sensor inputs. The

closer the input waveform is to a square wave, the

lower the required input amplitude. Inversely,

a higher input amplitude is required the closer the

input waveform is to a triangular wave. Also note

that the input DC voltage must be set to be within

the common-mode input voltage range.

If noise on the Hall inputs is a problem, that noise

must be excluded by inserting capacitors across

the inputs. Those capacitors must be located as

close as possible to the input pins.

When the Hall inputs for all three phases are in the

same state, all the outputs will be in the off state.

If a Hall sensor IC is used to provide the Hall

inputs, those signals can be input to one side

(either the + or − side) of the Hall effect sensor

signal inputs as 0 to VCC level signals if the other

side is held fixed at a voltage within the

common-mode input voltage range that applies

when a Hall effect sensors are used.

8. Forward/Reverse Switching:

The motor rotation direction can be switched using

the F/R pin. However, the following notes must be

observed if the motor direction is switched while

the motor is turning.

• This IC is designed to avoid through currents

when switching directions. However, increases

in the motor supply voltage (due to

instantaneous return of motor current to the

power supply) during direction switching may

cause problems. The values of the capacitors

inserted between power and ground must be

increased if this increase is excessive.

• If the motor current after direction switching

exceeds the current limit value, the PWM drive

side outputs will be turned off, but the opposite

side output will be in the short-circuit braking

state, and a current determined by the motor

back EMF voltage and the coil resistance will

flow. Applications must be designed so that this

current does not exceed the ratings of the output

transistors used. (The higher the motor speed at

which the direction is switched, the more severe

this problem becomes.)

9. Brake Switching:

The LB11923V provides short-circuit braking

implemented by turning the output transistors for

the high side for all phases (UH, VH, and WH) on.

(The opposite side transistors are turned off for all

phases.) Note that the current limiter does not

operate during braking. During braking, the duty is

set to 100%, regardless of the motor speed. The

current that flows in the output transistors during

braking is determined by the motor back EMF

voltage and the coil resistance. Applications must

be designed so that this current does not exceed

the ratings of the output transistors used. (The

higher the motor speed at which braking is

applied, the more severe this problem becomes.)

The braking function can be applied and released

with the IC in the start state. This means that

motor startup and stop control can be performed

using the brake pin with the S/S pin held at the low

level (the start state). If the startup time becomes

excessive, it can be reduced by controlling motor

startup and stop with the brake pin rather than with

the S/S pin. (Since the IC goes to the power saving

state when stopped, enough time for the VCO

circuit to stabilize will be required at the beginning

of the motor start operation.)

10. Constraint Protection Circuit:

The LB11923V includes an on-chip constraint

protection circuit to protect the IC and the motor in

motor constraint mode. If the LD output remains

high (indicating the locked state) for a fixed period

in the start state, the upper side (external)

transistors are turned off. This time is set by the

capacitance of the capacitor attached to the

CROCK pin. A time of a few seconds can be set

with a capacitance of under 0.1 mF.

When VCC + 6.3 V:

The set time (in seconds) is 37 C (mF)

(eq. 6)

When VCC + 5.0 V:

The set time (in seconds) is 30 C (mF)

(eq. 7)

To clear the rotor constrained protection state, the

application must either switch to the stop state for

a fixed period (about 1 ms or longer) or turn off and

reapply power.

If the rotor constrained protection circuit is not used,

a 220 kW resistor and a 1500 pF capacitor must be

connected in parallel between the CSD pin and

ground. However, in that case, the clock disconnect

protection circuit described below will no longer

function. Since the CSD pin also functions as the

power-on reset pin, if the CSD pin were connected

directly to ground, the IC would go to the power-on

reset state and motor drive operation would remain

off. The power-on reset state is cleared when the

CSD pin voltage rises above a level of about 0.64 V.

11. Clock Disconnect Protection Circuit:

If the clock input goes to the no input state when

the IC is in the start state, this protection circuit

will operate and turn off the PWM output. If the

clock is resupplied before the motor constraint

protection circuit operates, the IC will return to the

drive state, but if the motor constraint protection

circuit does operate, the IC must either be set

temporarily (approximately 1 ms or over) to the

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