H-Bridge and Dual Half Bridge Driver IC

TLE7181EM

Description and Electrical Characteristics

Data Sheet

12

Rev 1.1, 2010-09-30

5.1.5

100% D.C. charge pumps

100% D.C. charge pumps are implemented for each high side output stage. Therefore the high side output stages

can be switch on for an unlimited time. These integrated charge pumps can handle leakage currents which will be

caused by external MOSFETs and the TLE7181EM itself. They are not strong enough to drive a 99% duty cycle

for a longer time. the charge pumps are running when the driver is not in sleep mode and assure that the bootstrap

capacitors are charged as long as the user does not apply critical duty cycle for a longer time.

5.1.6

Reverse polarity protection of motor bridge

The TLE7181EM provides an additional RPP pin to protect motor bridge for reverse polarity. This RPP pin can

drive an additional external N-channel power MOSFET designed in between battery and the motor bridge. The

RPP pin is internally supplied by the two integrated 100% D.C. charge pumps. They are especially designed to

handle additional current which is needed to drive a the gate charge of the reverse polarity MOSFET. The

guarantied output current of the charge pumps is specified.

5.1.7

Sleep mode

If ENA pin is set to low, the ERR flag will be set to low and the output stages will be switched off.

After ENA pin is kept low for t

In Sleep mode the complete chip is deactivated. This means the internal supply structure of the TLE7181EM will

be switched off. This mode is designed for lowest current consumption from the power net of the car. The passive

clamping is active. For details see the description of passive clamping, see Chapter 5.2.9.

The TLE7181EM will wake up, if ENA is set to high.The ENA pin is 45V compatible, so ENA can be directly be

connected to the ignition key signal KL15.

5.1.8

Wake up

A special start up procedure is implemented into the TLE7181EM to guarantee charged bootstrap capacitors.

This start up procedure is automatically performed before normal H-bridge motor control with PWM/DIR is

possible.

If the ENA pin is set to high, the VREG voltage starts to increase. As soon as the under voltage threshold

VREG_UV is reached, both low side output stages will be switched on for a short period of time for fast charging

of the bootstrap capacitors. When the bootstrap capacitor voltage is high enough the auto start up procedure is

completed and the low side MOSFETs will be driven accoring the input pattern.

During wake up procedure the ERR signal is set to low. It will be set to high, if no error occurs at the TLE7181EM

and auto start procedure is completed.

To assure that the driver is finally in the normal operation mode, it is recommended to set the DRVDIS pin to high

for minimum 1us. After that procedure the output stages can be driven by PWM/DIR interface.