ZHCSDQ2C January 2015 – September 2018 TPS7B7701-Q1 , TPS7B7702-Q1
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
- 7.1 Overview
- 7.2 Functional Block Diagram
- 7.3
Feature Description
- 7.3.1 Fault Detection and Protection
- 7.3.2 Short-Circuit and Overcurrent Protection
- 7.3.3 Short-to-Battery and Reverse Current Detection
- 7.3.4 Thermal Shutdown
- 7.3.5 Integrated Reverse-Polarity Protection
- 7.3.6 Integrated Inductive Clamp
- 7.3.7 Undervoltage Lockout
- 7.3.8 Enable (EN, EN1, and EN2)
- 7.3.9 Internal Voltage Regulator (VCC)
- 7.3.10 Current Sense Multiplexing
- 7.3.11 Adjustable Output Voltage (FB, FB1, and FB2)
- 7.4 Device Functional Modes
- 8 Application and Implementation
- 9 Power Supply Recommendations
- 10Layout
- 11器件和文档支持
- 12机械、封装和可订购信息
8.2.2.4 Current-Limit Resistor Selection
The current at the LIMx pins (LIM, LIM1, and LIM2) is proportional to the load current at the OUTx (OUT, OUT1, and OUT2) pins and is internally connected to a current-limit comparator referenced to 1.233 V. The current limit is programmable through the external resistor connected at LIMx pin. Use Equation 5 to calculate the value of the external resistor, R(LIMx). The programmable current limit accuracy is 8% maximum across all conditions. The internal current limit of the device is set by shorting the LIM pin to ground. Because the current limit varies by 8%, Equation 6 shows how to calculate the minimum current limit value, and Equation 7 shows how to calculate the maximum current limit value.
where
Select a maximum current-limit value of 200 mA and use Equation 8 to calculate the value of R(LIMx).
Using Equation 8 yields a RLIMx value of 1.318 kΩ. The closest 1% resistor that can be selected is 1.33 kΩ. Now using Equation 7 and plugging in 1.33 kΩ for RLIMx yields a maximum current of 198.2 mA. Keep in mind this result does not include resistor tolerance in the calculation. To make sure that the current does not exceed the set amount, resistor tolerance must also be included in the equation.