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
8.2.2.2.9 BP Bypass Capacitor (C5)
Per the TPS40304 data sheet, a minimum 1.0-uF ceramic capacitance is required to stabilize the BP regulator. To limit regulator noise to less than 10 mV, the value of the bypass capacitor is calculated in Equation 31.
Equation 31. 
Because Q2 is larger than Q1, and the total gate charge of Q2 is 10 nC, a BP capacitor of 1.0 µF is calculated. A standard value of 1.0 µF is selected to limit noise on the BP regulator.