consists of two DMOS transistors connected in

series with common drain to act as a switch with

the voltage applied in both direction. A charge

pump takes the gates of the DMOS above the

supply voltage. The motor is controlled by the

control ’logic low voltage’ block that receives the

1

2

3

ITH

ITHCC

STALL CURRENT

2.3A

FRICTION

1.2A

VTH_HIGH

VTH_LOW

Figure 1. Functional timing diagram.

LIVE

COMMON

NC

GND

OUT

OUT

NC

V+

GND

NC

GND

SHUNT

SHUNT

SHUNT

GND

RCEX

R_SHUNT

R_REF

M

C+

C_EX

R_EX

NC

NC

NC

VREF

Figure 2. Application schematic diagram.

All the necessary external components are shown in the application diagram. It is important to shunt the

motor with a device that limits the maximum over voltage to 40V. This is necessary when the power sup-

ply circuit is opened on motor power up. In this case the back E.M.F. must be clamped because there is

no other free wheel current path.

L9639

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