ZHCSDQ2C January 2015 – September 2018 TPS7B7701-Q1 , TPS7B7702-Q1
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
- 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器件和文檔支持
- 12機械、封裝和可訂購信息
8.2.2.3 Current Sense Resistor Selection
The current-sense outputs, SENSEx (SENSE, SENSE1, and SENSE2), are proportional to the output current at the OUT, OUT1, and OUT2 pins with a factor of 1/198. An output resistor, R(SENSE), must be connected between the SENSEx pin and ground to generate a current sense voltage to be sampled by ADC. Use Equation 2 to calculate the voltage at SENSEx pin (V(SENSEx)).
where
For this example, select 1.5 kΩ as a value for R(SENSEx). Do not consider the resistor and current-sense accuracy.
For a load current of 198 mA, use Equation 3 to calculate the value of V(SENSEx).
To avoid any overlap between normal operation and current-limit or short-to-ground phase, using Equation 4 to select the value of the SENSE resistor is recommended.
where
- 198 is the output current to current-sense ratio
- 2.4 V is the minimum possible voltage at the SENSEx pin under a short-circuit fault case
- IOmax is the maximum possible output current under normal operation
To stabilize the current-sense loop, connecting a 1-µF ceramic capacitor at the SENSE, SENSE1, or SENSE2 pin is required. Table 4 lists the current sense accuracy across temperature.
Table 4. Current Sense Accuracy
| OUTPUT CURRENT | CURRENT SENSE ACCURACY |
|---|---|
| 5 mA to 10 mA | 20% |
| 10 mA to 50 mA | 10% |
| 50 mA to 100 mA | 5% |
| 100 mA to 300 mA | 3% |