5

Pin Descriptions

NAME

NUMBER

DESCRIPTION

DRAIN

1

The input to the DRAIN pin senses the drain of a power MOSFET Output Motor Driver. The DRAIN volt-

age is an image of the current flowing through the power MOSFET. By limiting this voltage, the torque of

the motor can be controlled.

TRIGGER

2

The TRIGGER input is an analog voltage control level used to fix the duty-cycle at the DRAIN Output. A

voltage level here is determined by a potentiometer adjustment. The TRIGGER voltage level is com-

pared with the triangle signal from the internal oscillator to produce a pulse-width modulated signal.

GND

3

Negative pole of the battery or system ground reference.

OSC

4

Oscillator output normally terminated in a charge/discharge capacitor. A constant current is flowing in

and out to charge and discharge the external capacitor.

TORQUE

5

The TORQUE input is a reference level adjustment for torque control. The voltage reference is compared

DELAY

6

An external capacitor at the DELAY output is used to delay the torque control action. The external ca-

pacitor at the DELAY pin will start to be charged if a MOSFET output over-current condition is detected.

The purpose of the capacitor is to delay the disabling action of the signal GATE drive.

GATE

7

The GATE output drives the Gate of the Power MOSFET.

8

Positive pole of the battery or Power Supply Voltage, nominally 7.5V.

+

-

NOTE: The value chosen for the torque level set pot is dependent on the type of power MOSFET and motor characteristics.

The TRIGGER is a combined SW/Speed Control function. Motor speed increases as the TRIGGER voltage decreases.

FIGURE 2. TYPICAL OPERATING CIRCUIT SHOWING THE HIP9021IB AS AN N-CHANNEL MOSFET DRIVER IN A PORTABLE

BATTERY ELECTRIC DRILL APPLICATION

1nF

3.3

µF

PORTABLE

ELECTRIC

DRILL MOTOR

OSCILLATOR

CONTROL

DRAIN

TRIGGER

GATE

TORQUE

OSC

DELAY

HIP9021

GND

TORQUE

LEVEL SET

SPEED

CONTROL

GC

+

1nF

180K

5.6K

100K

470K

200K

270K

1

µF

7.5V

330

Ω

15K

RFP45N03L

SW

POWER

N-CHANNEL

MOSFET

+

-

HIP9021