AM2908

Motor Driver ICs

AMtek semiconductors

July. 2020 V0.2

- 7 -

1) H-Bridge basic operating mode：

a) Forward mode

Definition：When INA=H，INB=L，then OUTA=H，OUTB=L

b) Reverse mode

Definition：When INA=L，INB=H，then OUTA=L，OUTB=H

c) Brake mode

Definition：When INA=INB= H，then

OUTA=OUTB=L

d) Stop mode

Definition：When INA=INB= L，then

OUTA=OUTB=Hi-Z

Q2

M

Q4

ON

OFF

OFF

ON

Q3

Q1

Q2

M

Q4

OFF

ON

ON

OFF

Q3

Q1

Q2

M

Q4

OFF

OFF

ON

ON

Q3

Q1

Q2

M

Q4

OFF

OFF

OFF

OFF

Q3

Q1

a) Forward mode

b) Reverse mode

c) Brake mode

d) Stop mode

1) Thermal shutdown protection (TSD)

If the IC junction temperature exceeds 175℃ (Typ.), the internal overtemperature protection function will

be triggered, all FETs in the H-bridge are disabled, that will ensure the safety of customers' products. If the

IC junction temperature falls to 120℃(Typ.), the IC resumes automatically.

2) Overcurrent protection (OCP)

When the IC conducts a large current, 8.0A (Typ), the internal overcurrent protection function will be

triggered, the H-bridge are disabled (Hiz state). After approximately 5.3ms, the bridge is re-enabled

automatically.

Overcurrent conditions on both high and low-side devices, that is, a short to ground, supply, or across the

motor winding all result in an overcurrent shutdown.

3) nFAULT table

Protection Functionality

Condition

H-Bridge Becomes

nFAULT Becomes

Recovery

Overcurrent (OCP)

Disable

Low

T

Thermal shutdown(TSD)

Disable

Low

Tj < 120℃

Undervoltage (UVLO)

VCC < 8.7V

Disable

Low

VCC > 9.4V