BTS7960 Просмотр технического описания (PDF) - Infineon Technologies

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BTS7960

High Current PN Half Bridge NovalithIC™ 43A, 7mΩ + 9mΩ

Infineon Technologies 

High Current PN Half Bridge

BTS 7960

Block Description and Characteristics

4.3

Protection Functions

The device provides integrated protection functions. These are designed to prevent IC

destruction under fault conditions described in the data sheet. Fault conditions are

considered as “outside” normal operating range. Protection functions are not to be used

for continuous or repetitive operation, with the exception of the current limitation

(Chapter 4.3.4). In a fault condition the BTS 7960 will apply the highest slew rate

possible independent of the connected slew rate resistor. Overvoltage, overtemperature

and overcurrent are indicated by a fault current IIS(LIM) at the IS pin as described in the

paragraph “Status Flag Diagnosis With Current Sense Capability” on Page 17 and

Figure 10.

In the following the protection functions are listed in order of their priority. Overvoltage

lock out overrides all other error modes.

4.3.1 Overvoltage Lock Out

To assure a high immunity against overvoltages (e.g. load dump conditions) the device

shuts the lowside MOSFET off and turns the highside MOSFET on, if the supply voltage

is exceeding the over voltage protection level VOV(OFF). The IC operates in normal mode

again with a hysteresis VOV(HY) if the supply voltage decreases below the switch-on

voltage VOV(ON). In H-bridge configuration, this behavior of the BTS 7960 will lead to

freewheeling in highside during over voltage.

4.3.2 Undervoltage Shut Down

To avoid uncontrolled motion of the driven motor at low voltages the device shuts off

(output is tri-state), if the supply voltage drops below the switch-off voltage VUV(OFF). The

IC becomes active again with a hysteresis VUV(HY) if the supply voltage rises above the

switch-on voltage VUV(ON).

4.3.3 Overtemperature Protection

The BTS 7960 is protected against overtemperature by an integrated temperature

sensor. Overtemperature leads to a shut down of both output stages. This state is

latched until the device is reset by a low signal with a minimum length of treset at the INH

pin, provided that its temperature has decreased at least the thermal hysteresis ∆T in the

meantime.

Repetitive use of the overtemperature protection might reduce lifetime.

4.3.4 Current Limitation

The current in the bridge is measured in both switches. As soon as the current in forward

direction in one switch (high side or low side) is reaching the limit ICLx, this switch is

deactivated and the other switch is activated for tCLS . During that time all changes at the

Data Sheet

13

Rev. 1.1, 2004-12-07

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