ZHCSLD0B May 2020 – June 2021 LM62435-Q1
PRODUCTION DATA
- 1 特性
- 2 應用
- 3 說明
- 4 Revision History
- 5 Device Comparison Table
- 6 Pin Configuration and Functions
- 7 Specifications
-
8 Detailed Description
- 8.1 Overview
- 8.2 Functional Block Diagram
- 8.3
Feature Description
- 8.3.1 EN Uses for Enable and VIN UVLO
- 8.3.2 MODE/SYNC Pin Operation
- 8.3.3 PGOOD Output Operation
- 8.3.4 Internal LDO, VCC UVLO, and BIAS Input
- 8.3.5 Bootstrap Voltage and VCBOOT-UVLO (CBOOT Pin)
- 8.3.6 Adjustable SW Node Slew Rate
- 8.3.7 Spread Spectrum
- 8.3.8 Soft Start and Recovery From Dropout
- 8.3.9 Output Voltage Setting
- 8.3.10 Overcurrent and Short Circuit Protection
- 8.3.11 Thermal Shutdown
- 8.3.12 Input Supply Current
- 8.4 Device Functional Modes
- 9 Application and Implementation
- 10Power Supply Recommendations
- 11Layout
- 12Device and Documentation Support
- 13Mechanical, Packaging, and Orderable Information
9.2.2.11 External UVLO
In some cases, an input UVLO level different than that provided internal to the device is needed. This can be accomplished by using the circuit shown in Figure 9-4. The input voltage at which the device turns on is designated VON while the turnoff voltage is VOFF. First, a value for RENB is chosen in the range of 10 kΩ to 100 kΩ, then Equation 12 is used to calculate RENT and VOFF. RENB is typically set based on how much current this voltage divider must consume. RENB can be calculated using Equation 11.
Equation 11. 
Figure 9-4 UVLO Using ENEquation 12. 
where
- VON = VIN turnon voltage
- VOFF = VIN turnoff voltage
- IDIVIDER = voltage divider current