ZHCSNC8A February 2021 – March 2021 TPS541620
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, Internally Compensated Advanced-Current-Mode Control
- 7.3.2 Enable and UVLO
- 7.3.3 Internal LDO
- 7.3.4 Pre-biased Output Start-up
- 7.3.5 Current Sharing
- 7.3.6 Frequency Selection and Minimum On-Time and Off-Time
- 7.3.7 Ramp Compensation Selection
- 7.3.8 Soft Start
- 7.3.9 Remote Sense Function
- 7.3.10 Adjustable Output Voltage
- 7.3.11 Power Good
- 7.3.12 Overcurrent Protection
- 7.3.13 Overvoltage and Undervoltage Protection
- 7.3.14 Overtemperature Protection
- 7.3.15 Frequency Synchronization
- 7.4 Device Functional Modes
-
8 Application and Implementation
- 8.1 Application Information
- 8.2
Typical Application - Dual Independent Outputs
- 8.2.1 Design Requirements
- 8.2.2
Detailed Design Procedure
- 8.2.2.1 Switching Frequency
- 8.2.2.2 Output Inductor Selection
- 8.2.2.3 Output Capacitor
- 8.2.2.4 Input Capacitor
- 8.2.2.5 Output Voltage Resistors Selection
- 8.2.2.6 Adjustable Undervoltage Lockout
- 8.2.2.7 Bootstrap Capacitor Selection
- 8.2.2.8 BP5 Capacitor Selection
- 8.2.2.9 PGOOD Pullup Resistor
- 8.2.2.10 Current Limit
- 8.2.2.11 Soft-Start Time Selection
- 8.2.2.12 MODE1 and MODE2 Pins
- 8.2.3 Application Curves
- 8.2.4
Typical Application - 2-Phase Operation
- 8.2.4.1 Design Requirements
- 8.2.4.2
Detailed Design Procedure
- 8.2.4.2.1 Switching Frequency
- 8.2.4.2.2 Output Inductor Selection
- 8.2.4.2.3 Output Capacitor
- 8.2.4.2.4 Input Capacitor
- 8.2.4.2.5 Output Voltage Resistors Selection
- 8.2.4.2.6 Adjustable Undervoltage Lockout
- 8.2.4.2.7 Bootstrap Capacitor Selection
- 8.2.4.2.8 BP5 Capacitor Selection
- 8.2.4.2.9 PGOOD Pullup Resistor
- 8.2.4.2.10 Current Limit
- 8.2.4.2.11 Soft-Start Time Selection
- 8.2.4.2.12 MODE1 Pin
- 8.2.4.3 Application Curves
- 9 Power Supply Recommendations
- 10Layout
- 11Device and Documentation Support
- 12Mechanical, Packaging, and Orderable Information
封裝選項
機(jī)械數(shù)據(jù) (封裝 | 引腳)
- RPB|25
散熱焊盤機(jī)械數(shù)據(jù) (封裝 | 引腳)
訂購信息
8.2.2.6 Adjustable Undervoltage Lockout
The undervoltage lockout (UVLO) is adjusted using the external voltage divider network of RENT and RENB. The UVLO has a threshold for power up when the input voltage is rising. UVLO has another threshold for power down or brownouts when the input voltage is falling. For this example design, the supply is set to turn on and start switching once the input voltage increases above 6 V (UVLO start or enable). After the regulator starts switching, it continues to do so until the input voltage falls below 5.5 V (UVLO stop or disable). In this example, these start and stop voltages set by the EN resistor divider are selected to have more hysteresis than the internally fixed VIN UVLO. Equation 21 can be used to calculate the values for the upper resistor. For these equations to work, VSTART must be 1.1 × VSTOP due to the voltage hysteresis of the EN pin. To set the start voltage, first select the bottom resistor (REN_B). The recommended value is between 1 kΩ and 100 kΩ. This example uses a 10-kΩ resistor.
For the voltages specified, the standard resistor value used for RENT is 39.2 k? and for RENB is 10 k?.
