UC184xA/284xA/384xA

PRODUCT DA T ABOOK 1996/1997

Copyright © 1995

Rev. 1.2

12/95

6

TYPICAL APPLICATION CIRCUITS

FIGURE 3. — CURRENT SENSE SPIKE SUPPRESSION

FIGURE 4. — MOSFET PARASITIC OSCILLATIONS

6

Q1

V

CC

DC BUS

5

R

S

R

1

UCx84xA

7

UCx84xA

3

5

6

7

R

S

C

Q1

V

CC

DC BUS

I

PK

I

1.0V

R

S

CHANGE

FIGURE 5. — EXTERNAL DUTY CYCLE CLAMP AND MULTI-UNIT SYNCHRONIZATION

A resistor (R

& ringing caused by the MOSFET input capacitance and any

inductance in series with the gate drive. (Note: It is very important to

have a low inductance ground path to insure correct operation of the

I.C. This can be done by making the ground paths as short and as

wide as possible.)

The RC low pass filter will eliminate the leading edge current spike

caused by parasitics of Power MOSFET.

f = (R

1.44

f = R

R

B

Precision duty cycle limiting as well as synchronizing several parts is

possible with the above circuitry.

2

6

7

R

B

R

A

5

1

84

3

555

TIMER

4

5

8

To other

UCx84xA devices

0.01

UCx84xA