INT201

F

2/96

4

Figure 6. Using the INT202 and INT201 to Drive a Switched Reluctance Motor.

General Circuit Operation (cont.)

The bootstrap capacitor must be large

enough to provide bias current over the

entire on time interval of the high-side

driver without significant voltage sag or

decay. The MOSFET gate charge must

also be supplied at the desired switching

frequency. Figure 5 shows the maximum

high-side on time versus gate charge of

the external MOSFET.

Applications

with extremely long high-side on times

require special techniques discussed in

AN-10.

A three-phase switched reluctance motor

example using the INT202/201 is given

in Figure 6. The LS IN signal directly

controls MOSFET Q1.

Unlike the

INT200, the INT202 allows both the

low and high-side drivers to be on at the

same time, as this is required in

applications where the load is placed

between the low and high-side output

MOSFETs.

PI-1468-042695

HV+

VDD

CONTROL

HV-

12

34

87

65

12

34

87

65

INT201

INT202

PHASE 1

PHASE 2

PHASE 3

3-PHASE

SRM

D1

C2

C1

R1

R2

D2

D3

Q2

Q1