Data Sheet

14

Rev. 1.0, 2010-05-28

High Current H-Bridge

BTM7745G

Block Description and Characteristics

6.3.2

Undervoltage Shut Down

To avoid uncontrolled motion of the driven motor at low voltages the device shuts off (both outputs are tri-state),

if the supply voltage

V

becomes active again with a hysteresis

V

6.3.3

Overtemperature Protection

The BTM7745G is protected against overtemperature by integrated temperature sensors. Each half bridge, which

consists of one high side and one low side switch, is protected by one temperature sensor located in the high side

switch. Both temperature sensors function independently. A detection of overtemperature through temperature

sensor leads to a shut down of both switches in the half bridge. This state is latched until the device is reset by a

temperature has decreased at least the thermal hysteresis

ΔT in the meantime.

Overtemperature protection is available up to supply voltage

V

For sufficient over temperature protection please consider also operation below the limitations outlined in Figure

4 and Figure 5.

Repetitive use of the overtemperature protection might reduce lifetime.

6.3.4

Current Limitation

The current in the bridge is measured in all four switches. As soon as the current in forward direction in one switch

Unintentional triggering of the current limitation by short current spikes (e.g. inflicted by EMI coming from the

motor) is suppressed by internal filter circuitry. Due to thresholds and reaction delay times of the filter circuitry the

I

L

t

I

CLx

t

CLS

I

CLx 0

1. 5*t

CLS

t

O

O

5V

V

ST

Figure 10

Timing Diagram Current Limitation and Status Flag