SA5901

HANGZHOU SILAN MICROELECTRONICS CO.,LTD

REV:1.3

2006.02.27

Http: www.silan.com.cn

Page 10 of 24

FUNCTION DESCRIPTION

H-bridge driver

(Gain setting)

Driver input resistance is 11k

Ω (typ.) for CH1, CH3 and CH4 and 7.5 kΩ for CH2.

Calculate driver gain with the under-mentioned expression and set it.

Ch1, Ch3, Ch4

GV=20log|

R

11K

55K

Ch2

GV=20log|

R

7.5K

110K

The power supply of drive output stage is HVCC pin (36-pin) and that of pre-drive circuit is VSYS2 pin (15-pin).

Attach by-pass capacitor (approximately 0.1

µF) to the legs of this IC between the power supplies.

(Mute function)

Brake function and mute function are assigned to CH1 and other channels of the four channels respectively.

When BRAKE1 pin (23-pin) has been set to “H”, the output of CH1 becomes “L”for both pin 31 and pin 32, and

enters a brake mode.

When MUTE2 pin (21-pin) has been set to “H”, the output of CH2 is muted.

When MUTE34 pin (19-pin) has been set to “L”, the output of CH3 and that of CH4 are muted simultaneously.

(VREF drop mute)

When the voltage impressed to VREF pin (16-pin) is 1.0V (typ.) orless, impedance of driver output becomes

‘

high”.

(Thermal shutdown)

When the chip temperature has been 150

°C(typ.), the output current is cut.

When the chip temperature has dropped to 120

°C(typ.), the output current begins to flow.

PWM power supply drive unit

This unit detects a maximum output level of drivers of four channels and performs the PWM supply of load

drive power supply (36-pin). This unit uses PNP transistor, coil, schottky diode and capacitor as external

component.

44

37

36

10P

2200P 100K

47

33

47

SBD

0.1

HVCC

PSW

PWMFIL

DC/DC converter

(Output voltage)

Booster circuit of 3.2V(typ.) can be configured with external components. This voltage varies depending on

addition of external components. How to set the voltage is as follows: