Very Low Standby Power Consumption Reverse Battery Protection Description
The VN920 , VN920-B5, VN920SO is a monolithic device made with STMicroelectronics Vipower M0-3 technology to drive any type of load with one side connected to ground. An active VCC pin voltage clamp protects the device from low energy peaks, and an active current limit combined with thermal shutdown and auto-restart protects the device from overload. The device integrates an analog current sense output that outputs current proportional to the load current. When the ground pin is disconnected, the unit automatically shuts down.
block diagram

Application diagram

Anti-battery ground protection network solution 1: Resistor in ground wire (R only). This can be used for any type of load. Below are instructions on how to size resistors.
1) rgnd≤600mv/(open) maximum value.
2) r ≥ (-v)/(-i), where -i is the DC reverse ground pin current, the power dissipation in R can be found in the Absolute Maximum Ratings section of the device datasheet (when V<0: In the case of reverse battery) is: Pd=(-VCC)2/rgnd
This resistor can be shared among several different HSDs. Note that the value of this resistor should be calculated using Equation (1), where i is the sum of the maximum on-state currents of the different devices. S(on)max
Note that if the microprocessor ground is not shared with the device ground, rwill will produce a shift (i*r) in the input threshold and state output values. In the case of multiple high-end drives sharing the same R, this change will depend on the number of devices. GNDS(on)maxGNDGND
If the calculated power dissipation results in a large resistor or multiple devices must share the same resistor, ST recommends solution 2 (see below).
Solution 2: Diode (D) in the ground wire. GND A resistor (R=1KΩ) should be connected in parallel to D if the device will drive an inductive load. GND GND This small signal diode can be safely shared among several different high speed drivers. Also in this case, if the microprocessor ground is not shared with the device ground, the presence of the ground network will create a shift (600 mV) in the input threshold and state output values. This offset does not change if multiple HSDs share the same diode/resistor network.
Load Dump Protection D (Voltage Transient Suppressor) is required if the load dump peak voltage exceeds the Vmax DC rating. The same applies if the device is exposed to transients on the V line greater than those shown in the ISO T/R 7637/1 table. Gamma Semiconductor Laser Cocos Cocos CI/O Protection: If a ground protection network is used and there is a negative transient on the V line, the control pin will be pulled negative. ST recommends inserting a resistor (R) in the line to prevent the μC I/O pins from locking up. Cocos Prote The values of these resistors are a compromise between the leakage current of the µC, hsd i/os (input level compatibility), and the current required (the latch is limited to µc i/os).
-V CRT I Latch Less than R Prot Less than (V, OH γC-V Ig-VGND) I IHMAX Calculation Example:
For V=-100V and I≥20mA; VμC≥4.5V 5KΩ≤R≤65KΩ. Cathode ray tube blocking Oh Plott's recommended rvalue is 10kΩ. Prot