OM9375 データシートの表示（PDF） - Omnirel Corp => IRF

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OM9375

FULL-FEATURED POWER MODULE FOR DIRECT DRIVE OF 3-PHASE BRUSHLESS DC MOTORS

Omnirel Corp => IRF 

OM9375

Test/Inspection

SFB

Precap Visual Inspection

100%

Temperature Cycle

100%

Mechanical Shock

100%

Hermeticity (Fine and Gross Leak) 100%

Pre Burn-In Electrical

100%

Burn-In (160 hours)

100%

Final Electrical Test

-55°C, +25°C,

+125°C

Group A Testing

100%

Final Visual Inspection

100%

APPLICATIONS

SF

100%

N.A.

N.A.

100%

N.A.

N.A.

+25°C

N.A.

100%

SPP

100%

N.A.

N.A.

N.A.

N.A.

N.A.

+25°C

N.A.

100%

Start-Up Conditions

The OM9375 3-phase brushless DC motor

controller/driver is designed to drive fractional to

integral horsepower motors. To ensure proper

operation, it is necessary to ensure that the high-side

bootstrap capacitors are charged during initial start-

up. However, the method(s) used to ensure this may

be dependent upon the application. For example,

some applications may only require that OV_COAST

(pin 17) be connected to ground, either via a hardwire

connection or via a switch (Enable/Disable), before

applying Vcc. When Vcc is applied, the

controller/driver is forced into brake mode for

approximately 200µsec (all high-side drivers are

disabled and all low-side drivers are enabled).

This may not be adequate for other applications;

RC_BRAKE (pin 16) may have to be momentarily

connected to ground via a switch, either manually or

electronically (ref. Figure 3). Note that with the

component values shown in Figure 3, RC_BRAKE is

pulled low for approximately 300 mSec after applying

Vcc at pin1.

Modes of Operation

Figures 4 and 5, shown on the following pages,

provide schematic representations of typical voltage-

mode and current-mode applications for the OM9375

controller/driver.

Figure 4 represents the implementation of a typical

voltage-mode controller for velocity control. A voltage

or speed command is applied to the noninverting input

of the error amplifier which is configured as a voltage

follower. The output of the error amplifier is compared

to a pulse width modulated ramp, and since motor

speed is nearly proportional to the average phase

output voltage, the speed is controlled via duty cycle

control. If a speed feedback loop is required, the

tachometer output can be connected to the inverting

input of the error amplifier via a loop compensation

network.

Figure 4 also shows the implementation of the cycle-

by-cycle current limit/overcurrent protection feature of

the OM9375. The load current is monitored via the

controller’s internal sense resistor. The current sense

signal is filtered and fed into the current sense amplifier

where the absolute value of ISH-ISL is multiplied by two

and biased up by 2.5 volts. The output of the current

sense amplifier is compared to a fixed reference, thus

providing cycle-by-cycle current limiting and/or

overcurrent protection as necessary. The typical peak

current threshold (ISH-ISL) is 0.20 volts; the typical

over current threshold (ISH-ISL) is 0.30 volts.

Figure 5 represents the implementation of a typical

current-mode controller for torque control. The load

current is monitored via the controller’s internal sense

resistor. The current sense signal is filtered and fed

into the current sense amplifier where the absolute

value of ISH-ISL is multiplied by two and biased up by

2.5 volts. Besides the implementation of the cycle-by-

cycle current limit/overcurrent protection feature of the

OM9375 discussed in the preceding paragraph, the

output of the current sense amplifier is fed into the error

amplifier which is configured as a differential amplifier.

An error signal representing the difference between the

current command input and the value of the amplified

current sense signal is produced. Then it is compared

to a pulse width modulated ramp and since torque is

nearly proportional to the average phase output

current, the torque is controlled via duty cycle control.

2.1 - 9

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