ZHCSCC8E March 2014 – July 2018 TPS92601-Q1 , TPS92602-Q1
UNLESS OTHERWISE NOTED, this document contains PRODUCTION DATA.
- 1 特性
- 2 应用范围
- 3 说明
- 4 修订历史记录
- 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 Fixed-Frequency PWM Control
- 7.3.2 Slope-Compensation Output Current
- 7.3.3 Boost-Current Limit
- 7.3.4 Oscillator and PLL
- 7.3.5 Control Loop Compensation
- 7.3.6 LED Open-Circuit Detection
- 7.3.7 Output Short-Circuit and Overcurrent Detection
- 7.3.8 Measuring LED Current During a Non-Failure Condition
- 7.3.9 LED Dimming Options
- 7.4 Device Functional Modes
-
8 Application and Implementation
- 8.1 Application Information
- 8.2
Typical Applications
- 8.2.1
Boost Regulator With Separate or Paralleled Channels
- 8.2.1.1 Design Requirements
- 8.2.1.2
Detailed Design Procedure
- 8.2.1.2.1 Switching Frequency
- 8.2.1.2.2 Maximum Output-Current Set Point
- 8.2.1.2.3 Output Overvoltage-Protection Set Point
- 8.2.1.2.4 Duty Cycle Estimation
- 8.2.1.2.5 Inductor Selection
- 8.2.1.2.6 Rectifier Diode Selection
- 8.2.1.2.7 Output Capacitor Selection
- 8.2.1.2.8 Input Capacitor Selection
- 8.2.1.2.9 Current Sense and Current Limit
- 8.2.1.2.10 Switching MOSFET Selection
- 8.2.1.2.11 Loop Compensation
- 8.2.1.3 Application Curves
- 8.2.2
Boost-to-Battery Regulator
- 8.2.2.1 Design Requirements
- 8.2.2.2
Detailed Design Procedure
- 8.2.2.2.1 Switching Frequency
- 8.2.2.2.2 Maximum Output-Current Set Point
- 8.2.2.2.3 Output Overvoltage-Protection Set Point
- 8.2.2.2.4 Duty Cycle Estimation
- 8.2.2.2.5 Inductor Selection
- 8.2.2.2.6 Rectifier Diode Selection
- 8.2.2.2.7 Output Capacitor Selection
- 8.2.2.2.8 Input Capacitor Selection
- 8.2.2.2.9 Current Sense and Current Limit
- 8.2.2.2.10 Switching MOSFET Selection
- 8.2.2.2.11 Loop Compensation
- 8.2.2.3 TPS92602y-Q1 Application Curves
- 8.2.1
Boost Regulator With Separate or Paralleled Channels
- 9 Power Supply Recommendations
- 10Layout
- 11器件和文档支持
- 12机械、封装和可订购信息
8.2.1.2.10 Switching MOSFET Selection
The TPS92602y-Q1 device drives a ground-referenced N-channel FET. The breakdown voltage is the output voltage plus any voltage spike, with 30% added for a safety margin as shown in Equation 34.
Select an N-channel FET with breakdown voltage of 50 V.
Estimate the rDS(on) and gate charge based on the desired efficiency target.
For a target of 95% efficiency with a 16-V input voltage at 1 A, maximum power dissipation is limited to 1.578 W. The main power-dissipating devices are the MOSFET, inductor, diode, current-sense resistor and the integrated circuit, the TPS92602y-Q1 device.
This assumption leaves 740 mW of power dissipation for the MOSFET. Allowing half for conduction and half for switching losses, we can determine a target rDS(on) and Q(GS) for the MOSFET by Equation 37 and Equation 38.
Calculate a target MOSFET gate-to-source charge of less than 29.2 nC to limit the switching losses to less than 250 mW.
Selecting a target MOSFET rDS(on) of 12 mΩ limits the conduction losses to less than 250 mW.