BTS5434G Datasheet, PDF (17/28 Pages) Infineon Technologies AG – Smart High-Side Power Switch PROFET TWO CHANNELS, 60MOHM

Smart High-Side Power Switch
BTS 5434G
4.2.2 Reverse Polarity Protection
In case of reverse polarity, the intrinsic body diode causes power dissipation. Additional
power is dissipated by the integrated ground resistor. Use following formula for
estimation of total power dissipation P_diss(rev) in reverse polarity mode.
∑ ^Pdiss(rev)
=
(V_DS(rev) ⋅ I_L) +
all channels
2 --^V----^b---^b---²--
R_GND
The reverse current through the intrinsic body diode has to be limited by the connected
load. The current through sense pins IS1 to IS4 has to be limited (please refer to
maximum ratings on Page 9). The current through the ground pin (GND) is limited
internally by R_GND. The over-temperature protection is not active during reverse polarity.
4.2.3 Over Voltage Protection
In addition to the output clamp for inductive loads as described in Section 4.1.3, there is
a clamp mechanism for over voltage protection. Because of the integrated ground
resistor, over voltage protection does not require external components.
As shown in Figure 12, in case of supply voltages greater than V_bb(AZ), the power
transistor switches on and the voltage across logic part is clamped. As a result, the
internal ground potential rises to V_bb - V_bb(AZ). Due to the ESD zener diodes, the
potential at pin IN1, IN2 and SEN rises almost to that potential, depending on the
impedance of the connected circuitry.
IN
R_IN
IS
SEN
R
SEN
ZD_ESD
logic
ZD_AZ
internal ground
R_GND
GND
Figure 12 Over Voltage Protection
VBB
OUT
V_OUT
OverVoltage .emf
4.2.4 Loss of Ground Protection
In case of complete loss of the device ground connections, but connected load ground,
the BTS 5434G securely changes to or keeps in off state.
Data Sheet
17
V1.0, 2004-01-23