ZHCSIY0 October 2018 TPS92515AHV-Q1
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 Detailed Description
- 8.1 Overview
- 8.2 Functional Block Diagram
- 8.3
Feature Description
- 8.3.1 General Operation
- 8.3.2 Current Sense Comparator
- 8.3.3 OFF Timer
- 8.3.4 OFF-Timer, Shunt FET Dimming or Shunted Output Condition
- 8.3.5 Internal N-channel MOSFET
- 8.3.6 VCC Internal Regulator and Undervoltage Lockout (UVLO)
- 8.3.7 Analog Adjust Input
- 8.3.8 Thermal Protection
- 8.3.9 Junction Temperature Relative Estimation
- 8.3.10 BOOT and BOOT UVLO
- 8.3.11 PWM (UVLO and Enable)
- 8.4 Device Functional Modes
-
9 Application and Implementation
- 9.1 Application Information
- 9.2
Typical Application
- 9.2.1 General Design Procedure
- 9.2.2 Design Requirements
- 9.2.3
Detailed Design Procedure
- 9.2.3.1 Calculating Duty Cycle
- 9.2.3.2 Calculate OFF-Time Estimate
- 9.2.3.3 Calculate OFF-Time Resistor ROFF
- 9.2.3.4 Calculate the Inductance Value
- 9.2.3.5 Calculate the Sense Resistance
- 9.2.3.6 Calculate Input Capacitance
- 9.2.3.7 Verify Peak Current for Inductor Selection
- 9.2.3.8 Calculate Output Capacitance
- 9.2.3.9 Calculate UVLO Resistance Values
- 9.2.4 Application Curves
- 9.3 Dos and Don'ts
- 10Power Supply Recommendations
- 11Layout
- 12器件和文档支持
- 13机械、封装和可订购信息
8.3.9 Junction Temperature Relative Estimation
The dominant power loss factors predict the junction temperature. These equations offer an estimate of device temperature for the use of considering different conversion scenarios. By adding the losses and using the device thermal impedance, a temperature can be predicted. In this case we consider losses internal to the device: Conduction loss in the MOSFET, an estimate of switching losses and Icq losses.
Equation 11. 
By expanding the terms an estimate can be calculated using Equation 12. Equation 12 is a good prediction in a design and layout similar to the orderable EVM. If other sources of heat rise are located near the TPS92515AHV-Q1 the device temperature also rises accordingly.
Equation 12. 