ZHCSQ77B February 2023 – June 2024 TPS25948
PRODUCTION DATA
- 1
- 1 特性
- 2 應用
- 3 說明
- 4 Device Comparison Table
- 5 Pin Configuration and Functions
- 6 Specifications
-
7 Detailed Description
- 7.1 Overview
- 7.2 Functional Block Diagram
- 7.3
Feature Description
- 7.3.1 Undervoltage Lockout (UVLO and UVP)
- 7.3.2 Overvoltage Lockout (OVLO)
- 7.3.3 Inrush Current, Overcurrent, and Short Circuit Protection
- 7.3.4 Analog Load Current Monitor
- 7.3.5 Reverse Current Protection
- 7.3.6 Overtemperature Protection (OTP)
- 7.3.7 Fault Response and Indication (FLT)
- 7.3.8 Supply Good Indication (SPLYGD/SPLYGD)
- 7.4 Device Functional Modes
- 8 Application and Implementation
- 9 Device and Documentation Support
- 10Revision History
- 11Mechanical, Packaging, and Orderable Information
8.3.2.2 Setting Output Voltage Rise Time (tR)
The slew rate (SR) needed to achieve the desired output rise time can be calculated as:
The CdVdt needed to achieve this slew rate can be calculated as:
Choose the nearest standard capacitor value as 3000 pF.
For this slew rate, the inrush current can be calculated as:
The average power dissipation inside the part during inrush can be calculated as:
For the given power dissipation, the thermal shutdown time of the device must be greater than the ramp-up time tR to avoid start-up failure. Figure 8-4 shows the thermal shutdown limit, for 0.8 W of power, the shutdown time is more than 10 s which is very large as compared to tR = 12 ms. Therefore, it is safe to use 12 ms as the startup time for this application.
Figure 8-4 Thermal Shut-Down Plot During
Inrush