TIDUCL3 February 2017
- 1 Overview
- 2 Resources
- 3 Features
- 4 Applications
- 5 Design Images
- 6 System Overview
-
7 System Design Theory
- 7.1 PCB and Form Factor
- 7.2 Optimizing Board Performance Based on LED String Voltage and Current
- 7.3 Switching Frequency
- 7.4 Output Overvoltage Protection (OVP)
- 7.5 Current Monitoring (IMON)
- 7.6 Thermal Foldback
- 7.7 Clock Generation (PWM)
- 7.8 Onboard Supply and Setting Duty Cycle
- 7.9 Buffering, Averaging, and Filtering
- 7.10 Boost Converter
- 8 Getting Started Hardware
- 9 Testing and Results
- 10Design Files
- 11Related Documentation
- 12About the Author
7.4 Output Overvoltage Protection (OVP)
As automotive environments are harsh, good designs incorporate protection features against harsh electrical transient scenarios. This TI Design incorporates output overvoltage protection (OVP) in the event of an output open circuit. This OVP prevents damaging the output capacitors, the rectifier diode, the switching field effect transistor (FET), the CSP pin, and the CSN pin of the device. Pins VIN, VCSP, and VCSN have a maximum voltage of 65 V, which means the OVP should be set so that the maximum output voltage does not reach 65 V. Also the resistors must be set to allow a hysteresis that will not go above that 65 V. The following equations show how to choose the values for the resistor divider going into the OVP pin.
