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AN1596 - APPLICATION NOTE

influence over the switch. A filament lamp or DC motor, for example, has in-rush currents that any switch

needs to handle. Solenoids and motors have an inductive effect and must lose the residual magnetism

when the current is turned off. External fault conditions can also stress the drivers and their associated

circuitry. The M0-3 High Side Driver can be divided in Analog and digital. This classification is done with

regard to diagnostic pin, which can be a two level signal pin or an analogue current sense pin. Diagnostic

information output helps the on Board microcontroller to quickly identify and isolate faults saving repair

time and often improving safety. High Side Drivers can reduce the size and weight of switch modules, and

where multiplexed systems are used, they dramatically reduce the size of the wiring harness.

Figure 2: Generic HSD Internal Block Diagram

STMicroelectronics HSDs are designed to provide the user with simple, self protected, remotely controlled

power switches. They have the general structure as shown in figure 2.

THE GENERAL FEATURES OF HIGH SIDE DRIVERS

Input

control pins and 5kV for Power pins). General rules concerning TTL logic should be applied to the input.

datasheets absolute maximum ratings section).

Internal power Supply

To accommodate the wide supply voltage range experienced by the logic and control functions, these

devices have an internal power supply. Some parts of the chip are only active when the input is high, the

charge pump for example. Therefore it is possible to conserve power when the device is idle. The new

M0-3 generation High Side Drivers supply current in the ON state is 5mA/channel. The internal power

consumption for the basic functions of the chip under any circumstances - even when the input is 0V - is

Vcc

clamp

Logic

Vcc

Status or

Current

sense

GND

OVERVOLTAGE

UNDERVOLTAGE

Power

CLAMP

Current

LIMITER

OVERTEMPERATURE

OPENLOAD

ON STATE

DRIVER

Isense =

OPENLOAD

OFF STATE

&

Vcc/OUT

SHORTED

OUT

GND

Input