AM5901AF44 datasheet(14/19 Pages) BCDSEMI

14 / 19 page

Data Sheet

Mar. 2007 Rev. 1. 3

BCD Semiconductor Manufacturing Limited

AM5901A

4-CHANNEL MOTOR DRIVER WITH POWER CONTROLLER

Application Information

H-Bridge Driver

1. Mute Function

Brake function is assigned to CH1, mute function

is assigned to other 3 channels.

(1) CH1 is in normal operation when the BRAKE

pin is low (high when CH1 mute on), and enters a

brake mode.

(2) CH2 is in normal operation when the MUTE2

pin is low (high when CH2 mute on).

(3) CH3,4 are in normal operation when the

MUTE34 pin is high (low when CH3,4 mute on).

2. VREF Drop Mute

When the voltage impressed to VREF terminal is

1.0V (Typ.) or less, impedance of driver output

becomes "high".

3. Thermal Shutdown

If the chip temperature rises above 140 oC, then

the thermal shutdown (TSD) circuit is activated

and the output current is cut. When the chip

temperature has dropped to 100oC, then output

current begins to flow.

4. Driver Gain

Driver input resistance is 11kΩ (CH1, CH3,

CH4) and 7.5kΩ (CH2). Driver gain can be calcu-

lated by the expression.

CH1,3,4

CH2

R is an external resistance

The power supply of driver output stage is HVCC

terminal and that of pre-driver circuit is VSYS2

terminal. Attach a by-pass capacitor (approxi-

mately 0.1µF) between the power supplies as

near as possible to this chip.

DC/DC Converter Control Circuit

1. Output Voltage

Booster circuit of voltage (VSYS1) can be

configured with external component. The voltage

is defined as follows.

2. Short-Circuit Protection Function

When the output of error amplifier is "H", if the

voltage of SPRT terminal has reached 1.245V

(Typ.) upon charging the terminal, switching of

SW terminal is disabled. Time to disable

switching depends on the capacitor of SPRT

terminal and it can be calculated by the

expression:

t=CSPRT * VTH/ISPRT (sec)

(VTH=1.245V, ISPRT=10µA)

R1 = External Resistance

R2 = External Resistance

R3 = 35k

Ω

R4 = 21k

Ω

GV=20 log |55k/(R+11k)|

GV=20 log | 110k/(R+7.5k)|

VSYS1

1.245V

R2*R4

R1*R3

(V)

(R2+R4)

(R1+R3)

R2*R4

(R2+R4)

VSYS1 = 1.245 *

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