OM9369 データシートの表示（PDF） - International Rectifier

部品番号

コンポーネント説明

メーカー

OM9369

FULL-FEATURED POWER MODULE FOR HIGH VOLTAGE DIRECT DRIVE OF 3-PHASE BRUSHLESS DC MOTOR

International Rectifier 

OM9369

QUAD SELECT INPUT (Pin 14) -- This input is used

to set the OM9369 in a half control or full control

chopping regime. When driven with a logic low level,

the OM9369 is in the half control mode, whereby only

the three lower (pull-down) power switches associated

with the Phase Outputs are allowed to chop. Alternately,

when driven with a logic high level, the OM9369 is

in the full control mode, where all six power switches

(pull-up and pull-down) associated with the Phase

Outputs are chopped by the PWM. During motor braking,

changing the logic state of the Quad Select Input

has no effect on the operation of the OM9369.

TACHOMETER OUTPUT (Pin 15) -- This output

provides a fixed width 5V pulse when any Hall-

effect Input (1, 2 or 3) changes state. The pulse width

of the Tachometer Output is set internally in the

OM9369 to 113µs (nominal). The average value of

the output voltage on pin 15 is directly proportional

to the motor's speed, so this output may be used

(with an external averaging filter) as a true tachometer

output, and fed back to the Speed Input (pin 23) to

sense the actual motor speed.

Note: Whenever pin 15 is high, the internal Hall-

effect position latches are inhibited (i.e. "latched"), to

reject noise during the chopping portion of the

commutation cycle, and this makes additional

commutations impossible. This means that in order

to prevent false commutation at a speed less than

the desired maximum speed, the highest speed as

observed at the Tachometer Output should be set

above the expected maximum value.

BRAKE / TACH TIMING INPUT (Pin 16) -- The

Brake/Tach Timing Input is a dual-purpose input.

Internal to the OM9369 are timing components tied

from pin 16 to Ground (a 51kΩ resistor and a

3300pF capacitor).These components set the minimum

pulse width of the Tachometer Output to 113µs, and

this time may be adjusted using external components,

according to the equation:

( ) T(tach) = 0.67 x (Ct + 3300pf) x Rt x 51kΩ (µs)

Rt + 51kΩ

The recommended range of external resistance (to

Ground) is 15kΩ to ∞, and the range of external

capacitance (to Ground) is 0pF to 0.01uF. With each

Tachometer Output pulse, the capacitor tied to pin

16 is discharged from approximately 3.33V to

approximately 1.67V by an internal timing resistor.

The Brake / Tach Timing Input has another function.

If this pin is pulled below the brake threshold

voltage, the OM9369 will enter the brake mode. The

brake mode is defined as the disabling of all three

high-side (pull-up) drivers associated with the Phase

Outputs, and the enabling of all three low-side (pull-

down) drivers.

OVERVOLTAGE / COAST INPUT (Pin 17) -- This

input may be used as a shutdown or an enable/

disable input to the OM9369. Also, since the

switching inhibit threshold is so tightly defined, this

input can be directly interfaced with a resistive

divider which senses the voltage of the motor

supply, Vm, for overvoltage conditions. A high level

(greater than the inhibit threshold) on pin 17 causes

the coast condition to occur, whereby all Phase

Outputs revert to a Hi-Z state and any motor current

which flowed prior to the Overvoltage/ Coast command

is commutated via the power "catch" rectifiers

associated with each Phase Output.

SOFT-START INPUT (Pin 18) -- The Soft-Start input

is internally connected to a 10µA (nominal) current

source, the collector of an NPN clamp/discharge

transistor, and a voltage comparator whose soft-

start/restart threshold is 0.2Vdc (nominal). An external

capacitor is connected from this pin to Ground (pin

19). Whenever the Vcc supply input drops below the

turn-on threshold, approximately 9Vdc, or the sensed

current exceeds the over-current threshold,

approximately 0.3V at the current sense amplifier,

the soft-start latch is set. This drives the NPN clamp

transistor which discharges the external soft-start

capacitor. When the capacitor voltage drops below

the soft-start/restart threshold and a fault condition

does not exist, the soft-start latch is cleared; the soft-

start capacitor charges via the internal current

source.

In addition to discharging the soft-start capacitor, the

clamp transistor also clamps the output of the error

amplifier internal to the controller IC, not allowing

the voltage at the output of the error amplifier to

exceed the voltage at pin 18, regardless of the inputs

to the amplifier. This action provides for an orderly

motor start-up either at start-up or when recovering

from a fault condition.

10

www.irf.com

Share Link: