ZHCSHA3D NOVEMBER 2009 – March 2018 TPS40303 , TPS40304 , TPS40305
PRODUCTION DATA.
- 1 特性
- 2 应用
- 3 说明
- 4 修订历史记录
- 5 Pin Configuration and Functions
- 6 Specifications
- 7 Detailed Description
-
8 Application and Implementation
- 8.1 Application Information
- 8.2
Typical Applications
- 8.2.1
Using the TPS40305 for a 12-V to 1.8-V Point-of-Load Synchronous Buck Regulator
- 8.2.1.1 Design Requirements
- 8.2.1.2
Detailed Design Procedure
- 8.2.1.2.1 Custom Design With WEBENCH® Tools
- 8.2.1.2.2 Selecting the Switching Frequency
- 8.2.1.2.3 Inductor Selection (L1)
- 8.2.1.2.4 Output Capacitor Selection (C12)
- 8.2.1.2.5 Peak Current Rating of Inductor
- 8.2.1.2.6 Input Capacitor Selection (C8)
- 8.2.1.2.7 MOSFET Switch Selection (Q1 and Q2)
- 8.2.1.2.8 Bootstrap Capacitor (C6)
- 8.2.1.2.9 VDD Bypass Capacitor (C7)
- 8.2.1.2.10 BP Bypass Capacitor (C5)
- 8.2.1.2.11 Short-Circuit Protection (R11)
- 8.2.1.2.12 Feedback Divider (R4, R5)
- 8.2.1.2.13 Compensation: (C2, C3, C4, R3, R6)
- 8.2.1.3 Application Curves
- 8.2.2
A High-Current, Low-Voltage Design Using the TPS40304
- 8.2.2.1 Design Requirements
- 8.2.2.2
Detailed Design Procedure
- 8.2.2.2.1 Selecting the Switching Frequency
- 8.2.2.2.2 Inductor Selection (L1)
- 8.2.2.2.3 Output Capacitor Selection (C12)
- 8.2.2.2.4 Peak Current Rating of Inductor
- 8.2.2.2.5 Input Capacitor Selection (C8)
- 8.2.2.2.6 MOSFET Switch Selection (Q1 and Q2)
- 8.2.2.2.7 Bootstrap Capacitor (C6)
- 8.2.2.2.8 VDD Bypass Capacitor (C7)
- 8.2.2.2.9 BP Bypass Capacitor (C5)
- 8.2.2.2.10 Short-Circuit Protection (R11)
- 8.2.2.2.11 Feedback Divider (R4, R5)
- 8.2.2.2.12 Compensation: (C2, C3, C4, R3, R6)
- 8.2.2.3 Application Curves
- 8.2.3
A Synchronous Buck Application Using the TPS40303
- 8.2.3.1 Design Requirements
- 8.2.3.2
Detailed Design Procedure
- 8.2.3.2.1 Selecting the Switching Frequency
- 8.2.3.2.2 Inductor Selection (L1)
- 8.2.3.2.3 Output Capacitor Selection (C12)
- 8.2.3.2.4 Peak Current Rating of Inductor
- 8.2.3.2.5 Input Capacitor Selection (C8)
- 8.2.3.2.6 MOSFET Switch Selection (Q1 and Q2)
- 8.2.3.2.7 Bootstrap Capacitor (C6)
- 8.2.3.2.8 VDD Bypass Capacitor (C7)
- 8.2.3.2.9 BP Bypass Capacitor (C5)
- 8.2.3.2.10 Short-Circuit Protection (R11)
- 8.2.3.2.11 Feedback Divider (R4, R5)
- 8.2.3.2.12 Compensation: (C2, C3, C4, R3, R6)
- 8.2.3.3 Application Curves
- 8.2.1
Using the TPS40305 for a 12-V to 1.8-V Point-of-Load Synchronous Buck Regulator
- 9 Power Supply Recommendations
- 10Layout
- 11器件和文档支持
- 12机械、封装和可订购信息
8.2.2.2.10 Short-Circuit Protection (R11)
The TPS40304 uses the negative drop across the low-side FET at the end of the OFF time to measure the inductor current. Allowing for 30% over maximum load and 20% rise in RDS(on)Q1 for self-heating, the voltage drop across the low-side FET at current limit is given by Equation 32.
Equation 32. 
The TPS40304 internal temperature coefficient helps compensate for the MOSFET RDS(on) temperature coefficient, so the current limit programming resistor is selected by Equation 33.
Equation 33. 