APPLICATION CIRCUIT

D2, D4 = 2A High speed diodes

D1, D3 = 1A High speed diodes

R1 = R2 = 2

Ω

L1 = L2 = 5 mH

)

trr

≤ 200 ns

FUNCTIONAL DESCRIPTION

The L295 incorporates two indipendent driver

channals with separate inputs and outputs, each

capable of driving an inductive load (see block

diagram).

The device is controlled by three micriprocessor

compatible digital inputs and two analog inputs.

These inputs are:

EN

chip enable (digital input, active low),

enables both channels when in the low

state.

channel inputs (digital inputs, active

high), enable each channel inde-

pendently. A channel is actived when

both EN and the appropriate channel

input are active.

to program the peak load currents.

.

Since the two channels are identical, only channel

one will be described.

The following description applies also the channel

When the channel is avtivated by low level on the

the output transistors Q1 and Q2 switch on and

current flows in the load according to the exponen-

tial law:

I

=

V

R1

( 1 − e

− R1 t

L1

)

where:

R1 and R2 are the resistance and in-

ductance of the load and V is the volt-

The current increases until the voltage on the ex-

=

At this point the comparator output, Vomp1, sete

the RS flip-flop, FF1, that turns off the output tran-

sistor, Q1. The load current flowing through D2, Q2,

I

= (

− R1 t

L1

−

R1

4/8

L295