ZHCSIW7B October 2018 – January 2020 TPS25982
PRODUCTION DATA.
- 1 特性
- 2 應用
- 3 說明
- 4 修訂歷史記錄
- 5 器件比較表
- 6 Pin Configuration and Functions
- 7 Specifications
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8 Detailed Description
- 8.1 Overview
- 8.2 Functional Block Diagram
- 8.3 Feature Description
- 8.4 Fault Response
- 8.5 Device Functional Modes
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9 Application and Implementation
- 9.1 Application Information
- 9.2
Typical Application: Standby Power Rail Protection in Datacenter Servers
- 9.2.1 Design Requirements
- 9.2.2
Detailed Design Procedure
- 9.2.2.1 Device Selection
- 9.2.2.2 Setting the Current Limit Threshold: RILIM Selection
- 9.2.2.3 Setting the Undervoltage Lockout Set Point
- 9.2.2.4 Choosing the Current Monitoring Resistor: RIMON
- 9.2.2.5 Setting the Output Voltage Ramp Time (TdVdt)
- 9.2.2.6 Setting the Load Handshake (LDSTRT) Delay
- 9.2.2.7 Setting the Transient Overcurrent Blanking Interval (tITIMER)
- 9.2.2.8 Setting the Auto-Retry Delay and Number of Retries
- 9.2.3 Application Curves
- 9.3 System Examples
- 10Power Supply Recommendations
- 11Layout
- 12器件和文檔支持
- 13機械、封裝和可訂購信息
8.3.3.4 Short-Circuit Protection
During an output short-circuit event, the current through the device increases very rapidly. When an output short-circuit is detected, the internal fast-trip comparator turns off the output within the tSC. The comparator employs a scalable threshold which is equal to 2.1 × ILIM. This enables the user to adjust the fast-trip threshold as per system needs rather than using a fixed threshold which may not be suitable for all systems. After a fast trip event, the device restarts in a current limited mode to try and restore power to the load quickly in case the fast trip was triggered by a transient event. However, if the fault is persistent, the device will stay in current limit causing the junction temperature to rise and eventually enter thermal shutdown. See Overtemperature Protection (OTP) section for details on the device response to overtemperature.
In some of the systems, for example servers or telecom equipment which house multiple hot-pluggable cards connected to a common supply backplane, there can be transients on the supply due to switching of large currents through the inductive backplane. This can result in current spikes on adjacent cards which could be potentially large enough to inadvertently trigger the fast-trip comparator of the eFuse. The TPS25982 uses a proprietary algorithm to avoid nuisance tripping in such cases thereby facilitating un-interrupted system operation.
Figure 46. Input Line Transient and Output Short-Circuit Response NOTE
To prevent the current limit/circuit breaker loop from interfering with the input line transient detection logic, TI recommends to set the ITIMER interval higher than 100 μs. Refer to Table 1 for more details on ITIMER.