ZHCSCY3E October 2014 – October 2018 LM5160 , LM5160A
PRODUCTION DATA.
- 1 特性
- 2 應用
- 3 說明
- 4 修訂歷史記錄
- 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
LM5160 Synchronous Buck (10-V to 60-V Input, 5-V Output, 1.5-A Load)
- 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 Feedback Resistor Divider - RFB1, RFB2
- 8.2.1.2.3 Switching Frequency - RON
- 8.2.1.2.4 Inductor - L
- 8.2.1.2.5 Output Capacitor - COUT
- 8.2.1.2.6 Series Ripple Resistor - RESR
- 8.2.1.2.7 VCC and Bootstrap Capacitors - CVCC, CBST
- 8.2.1.2.8 Input Capacitor - CIN
- 8.2.1.2.9 Soft-Start Capacitor - CSS
- 8.2.1.2.10 EN/UVLO Resistors - RUV1, RUV2
- 8.2.1.3 Application Curves
- 8.2.2 LM5160 Isolated Fly-Buck (18-V to 32-V Input, 12-V, 4.5-W Isolated Output)
- 8.2.3 LM5160A Isolated Fly-Buck (18-V to 32-V Input, 12-V, 4.5-W Isolated Output)
- 8.2.1
LM5160 Synchronous Buck (10-V to 60-V Input, 5-V Output, 1.5-A Load)
- 8.3 Do's and Don'ts
- 9 Power Supply Recommendations
- 10Layout
- 11器件和文檔支持
- 12機械、封裝和可訂購信息
7.3.6 On-Time Generator
The on-time of the LM5160 high-side MOSFET is determined by the RON resistor and is inversely proportional to the input voltage (VIN). The inverse relationship with VIN results in a nearly constant frequency as VIN is varied. Calculate the on-time from Equation 3 with RON expressed in Ohms.
To set a specific continuous conduction mode switching frequency (FSW expressed in Hz), determine the RON resistor from Equation 4.
RON must be selected for a minimum on-time (at maximum VIN) greater than 150 ns for proper operation. This minimum on-time requirement limits the maximum switching frequency of applications with relatively high VIN and low VOUT.