ZHCSBP7C October 2013 – December 2018 TPS24750 , TPS24751
UNLESS OTHERWISE NOTED, this document contains PRODUCTION DATA.
- 1 特性
- 2 应用
- 3 说明
- 4 修订历史记录
- 5 Device Comparison Table
- 6 Pin Configuration and Functions
- 7 Specifications
- 8 Parameter Measurement Information
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9 Detailed Descriptions
- 9.1 Overview
- 9.2 Functional Block Diagram
- 9.3 Feature Description
- 9.4 Device Functional Modes
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10Application and Implementation
- 10.1 Application Information
- 10.2
Typical Application
- 10.2.1 Design Requirements
- 10.2.2
Detailed Design Procedure
- 10.2.2.1
Power-Limited Start-Up
- 10.2.2.1.1 STEP 1. Choose RSENSE, RSET, and RIMON
- 10.2.2.1.2 STEP 2. Choose Power-Limit Value, PLIM, and RPROG
- 10.2.2.1.3 STEP 3. Choose Output Voltage Rising Time, tON, and Timing Capacitor CT
- 10.2.2.1.4 STEP 4. Calculate the Retry-Mode Duty Ratio
- 10.2.2.1.5 STEP 5. Select R1, R2, and R3 for UV and OV
- 10.2.2.1.6 STEP 6. Choose R4, R5, and C1
- 10.2.2.2 Alternative Design Example: Gate Capacitor (dv/dt) Control in Inrush Mode
- 10.2.2.3 Additional Design Considerations
- 10.2.2.1
Power-Limited Start-Up
- 10.2.3 Application Curves
- 10.3 System Examples
- 11Power Supply Recommendations
- 12Layout
- 13器件和文档支持
- 14机械、封装和可订购信息
9.3.10 PROG
A resistor from this pin to GND sets the maximum power permitted in the internal MOSFET during inrush. Do not apply a voltage to this pin. If the constant power limit is not desired, use a PROG resistor of 4.99 kΩ. To set the maximum power, use Equation 1.
where PLIM is the allowed power limit of the internal MOSFET. RSENSE is the load current monitoring resistor connected between the VCC pin and the SENSE pin. RPROG is the resistor connected from the PROG pin to GND. Both RPROG and RSENSE are in ohms and PLIM is in watts. PLIM is determined by the maximum allowed thermal stress of internal MOSFET, given by Equation 2.
where TJ(MAX) is the maximum desired transient junction temperature and TC(MAX) is the maximum case temperature prior to a start or restart. RӨJC(MAX) is the junction-to-case thermal impedance of the internal pass FET in units of °C/W. Both TJ(MAX) and TC(MAX) are in °C.