AN1088 Datasheet, PDF (1/14 Pages) STMicroelectronics – L6234 THREE PHASE MOTOR DRIVER

AN1088
®
APPLICATION NOTE
L6234 THREE PHASE MOTOR DRIVER
by Domenico Arrigo
INTRODUCTION
The L6234 is a DMOSs triple half-bridge driver with input supply voltage up 52V and output current of
5A. It can be used in a very wide range of applications.
It has been realized in Multipower BCD60II technology which allows the combination of isolated DMOS
transistors with CMOS and Bipolar circuits on the same chip. It is available in Power DIP 20 (16+2+2)
and in Power SO 20 packages.
All the inputs are TTL/CMOS compatible and each half bridge can be driven by its own dedicated input
and enable.
The DMOS structure has an intrinsic free wheeling body diode so the use of external diodes, which are
necessary in the bipolar configuration, can be avoided. The DMOS structure allows a very low quiescent
current of 6.5 mA typ. at Vs=42V , irrespective of the load.
DEVICE DESCRIPTION
The device is composed of three channels. Each channel is composed of a half bridge with two power
DMOS switches ( typ. Rdson of 300mW @ 25°C) and intrinsic free wheeling diodes. Each channel in-
cludes two TTL/CMOS and uP compatible comparators, and a logic block to interface the inputs with the
drivers. The device includes an internal bandgap reference of 1.22V, a 10V voltage reference to supply
the internal circuitry of the device, a central charge pump to drive the upper DMOS switch, thermal shut-
down protection and an internal hysteretic function which turns off the device when the junction tempera-
ture exceeds approximately 160 °C. Hysteresys is about 20 °C.
Figure 1. L6234 Block Diagram
C3
10nF
VCP
CHARGE
PUMP
IN1
C5
1µF
VREF
EN1
IN2
EN2
THERMAL
PROTECTION
IN3
EN3
VBOOT
V_REF
10V
GND
C4 220nF
D2
1N4148
D1
Vs
1N4148
Vs
Vs
C2
T1
100nF
OUT1
C1
100µF
T2
BRUSHLESS
MOTOR
WINDINGS
T3
OUT2
T4
SENSE1
T5
OUT3
T6
SENSE2
D98IN940A
R_SENSE
April 2001
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