ZHCSB85F November 2011 – October 2021 TPS62140 , TPS62140A , TPS62141 , TPS62142 , TPS62143
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
9.2.2.4 Output Filter and Loop Stability
The devices of the TPS6214x family are internally compensated to be stable with L-C filter combinations corresponding to a corner frequency to be calculated with Equation 12:
Proven nominal values for inductance and ceramic capacitance are given in Table 9-2 and are recommended for use. Different values may work, but care must be taken on the loop stability, which is affected. More information including a detailed L-C stability matrix can be found in Optimizing the TPS62130/40/50/60 Output Filter Application Report.
The TPS6214x devices, both fixed and adjustable versions, include an internal 25 pF feed-forward capacitor, connected between the VOS and FB pins. This capacitor impacts the frequency behavior and sets a pole and zero in the control loop with the resistors of the feedback divider, per equations Equation 13 and Equation 14:
Though the TPS6214x devices are stable without the pole and zero being in a particular location, adjusting their location to the specific needs of the application can provide better performance in power-save mode and/or improved transient response. An external feed-forward capacitor can also be added. A more detailed discussion on the optimization for stability vs transient response can be found in Optimizing Transient Response of Internally Compensated DC-DC Converters Application Report and Feedforward Capacitor to Improve Stability and Bandwidth of TPS621/821-Family Application Report.