ZHCSJ68A December 2018 – September 2021 LM34936-Q1
PRODUCTION DATA
- 1 特性
- 2 應(yīng)用
- 3 說明
- 4 Revision History
- 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 Valley/Peak Current Mode Control with Slope Compensation
- 7.3.2 VCC Regulator and Optional BIAS Input
- 7.3.3 Enable/UVLO
- 7.3.4 Soft Start
- 7.3.5 Overcurrent Protection
- 7.3.6 Average Input/Output Current Limiting
- 7.3.7 Operation Above 28-V Input
- 7.3.8 CCM Operation
- 7.3.9 Frequency and Synchronization (RT/SYNC)
- 7.3.10 Frequency Dithering
- 7.3.11 Output Overvoltage Protection (OVP)
- 7.3.12 Power Good (PGOOD)
- 7.3.13 Gm Error Amplifier
- 7.3.14 Integrated Gate Drivers
- 7.3.15 Thermal Shutdown
- 7.4 Device Functional Modes
-
8 Application and Implementation
- 8.1 Application Information
- 8.2
Typical Application
- 8.2.1 Design Requirements
- 8.2.2
Detailed Design Procedure
- 8.2.2.1 Custom Design with WEBENCH Tools
- 8.2.2.2 Frequency
- 8.2.2.3 VOUT
- 8.2.2.4 Inductor Selection
- 8.2.2.5 Output Capacitor
- 8.2.2.6 Input Capacitor
- 8.2.2.7 Sense Resistor (RSENSE)
- 8.2.2.8 Slope Compensation
- 8.2.2.9 UVLO
- 8.2.2.10 Soft-Start Capacitor
- 8.2.2.11 Dither Capacitor
- 8.2.2.12 MOSFETs QH1 and QL1
- 8.2.2.13 MOSFETs QH2 and QL2
- 8.2.2.14 Frequency Compensation
- 8.2.3 Application Curves
- 9 Power Supply Recommendations
- 10Layout
- 11Device and Documentation Support
- 12Mechanical, Packaging, and Orderable Information
封裝選項
機械數(shù)據(jù) (封裝 | 引腳)
- PWP|28
散熱焊盤機械數(shù)據(jù) (封裝 | 引腳)
- PWP|28
訂購信息
8.2.2.8 Slope Compensation
For stable current loop operation and to avoid sub-harmonic oscillations, select the slope capacitor based on Equation 23:
This slope compensation results in “dead-beat” operation, in which the current loop disturbances die out in one switching cycle. Theoretically a current mode loop is stable with half the “dead-beat” slope (twice the calculated slope capacitor value in Equation 23). A smaller slope capacitor results in larger slope signal which is better for noise immunity in the transition region (VIN~VOUT). A larger slope signal, however, restricts the achievable input voltage range for a given output voltage, switching frequency, and inductor. For this design CSLOPE = 220 pF is selected for better transition region behavior while still providing the required VIN range. This selection of slope capacitor, inductor, switching frequency, and inductor satisfies the COMP range limitation explained in Section 7.3.13.