ZHCSB86E November 2011 – October 2021 TPS62150 , TPS62150A , TPS62151 , TPS62152 , TPS62153
PRODUCTION DATA
- 1 特性
- 2 應用
- 3 說明
- 4 Revision History
- 5 Device Comparison Table
- 6 Pin Configuration and Functions
- 7 Specifications
- 8 Detailed Description
- 9 Application and Implementation
- 10Power Supply Recommendations
- 11Layout
- 12Device and Documentation Support
- 13Mechanical, Packaging, and Orderable Information
9.2.2.2.2.3 Soft-Start Capacitor
A capacitance connected between the SS/TR pin and AGND allows a user-programmable start-up slope of the output voltage. A constant-current source supplies 2.5 μA to charge the external capacitance. The capacitor required for a given soft-start ramp time for the output voltage is given by:
where
- CSS is the capacitance (F) required at the SS/TR pin
- tSS is the desired soft-start ramp time (s)
DC bias effect: High capacitance ceramic capacitors have a DC bias effect, which has a strong influence on the final effective capacitnace. Therefore, selecting the right capacitor value requires careful choice. Package size and voltage rating in combination with delectric material are responsible for differences betweeen the rated capacitor value and the effective capacitance.