حفاظت مدار محدودکننده‌های ولتاژ گذرا (تی وی اس) تجهیزات حفاظت در برابر اضافه‌ولتاژ گذرا (اس پی دی)

Product Attributes

Introduction

The LMX960D80 high-side N-channel FET (N_FET) driver works with an internal MOSFET as a hot-swap circuit with power limiting capability. The driver is designed to control the inrush current to a load when a board is inserted into a live backplane or other hot power source, thereby limiting the voltage drop of the backplane supply voltage and the dv/dt of the voltage applied to the load. The current limit in the external series-pass N-channel MOSFET is programmable. Input undervoltage and overvoltage lockout levels are programmable via a resistor divider network. The LMX960D80 automatically restarts at a fixed duty cycle programmed by a timer capacitor. The LMX960D80 is available in a 10-pin DFN 3×3 package.

The LMX960D80 features programmable current limiting; sustained current limiting will cause the series-pass device to shut down. In this case, after the fault is cleared, the LMX960D80 will attempt recovery an unlimited number of times. The circuit breaker function rapidly shuts down the series-pass device upon detection of a severe overcurrent condition. Programmable UVLO and OVP circuits shut down the LMX960D80 when the system input voltage exceeds the required operating range. In addition to programmable current limiting, the LMX960D80 also monitors and limits the maximum power dissipation in the series-pass device to ensure operation within the safe operating area. Sustained current limiting or power limiting will both cause the series-pass device to shut down. In this case, after the fault is cleared, the LMX960D80 will attempt recovery an unlimited number of times. The circuit breaker function rapidly shuts down the series-pass device upon detection of a severe overcurrent condition.

When the input supply voltage is within the operating range defined by the programmable UVLO and overvoltage lockout levels, the series-pass MOSFET is enabled. Typically, the UVLO level at VIN is set via a resistor divider. When VIN falls below the UVLO level, the internal 5μA current source at UVLO is enabled, the current source at OVLO is disabled, and OUT is disconnected. As VIN rises and causes the voltage at UVLO to exceed 2.5V, the 5μA current source at UVLO is disabled and the voltage at UVLO rises, providing hysteresis for this threshold. When the UVLO pin voltage exceeds 2.5V and the insertion time delay expires, the 30μA current source at the GATE pin turns on OUT. The minimum possible UVLO level at VIN can be set by connecting the UVLO pin to VIN. In this case, OUT is enabled when the VIN voltage reaches the VINEN threshold.

By programming the UVLO and OVLO thresholds, the LMX960D80 enables the series-pass MOSFET when the input supply voltage is within the required operating range. If VIN falls below the UVLO threshold or rises above the OVLO threshold, OUT turns off, cutting power to the load. Hysteresis is provided for each threshold. There are four methods to configure UVLO and OVLO for setting hysteresis thresholds.

Features

• Wide operating range: 9V ~ 40V
• Adjustable current limit
• Circuit breaker function for severe overcurrent events
• Internal high-side charge pump and gate driver for N-channel MOSFET
• Adjustable undervoltage lockout (UVLO)
• Adjustable overvoltage lockout (OVP)
• Auto-restart capability
• 10-pin DFN package

Applications

• Server backplane systems
• Base station power distribution systems
• 12–24V and 36V industrial systems
• Programmable logic circuits
• Solid-state circuit breakers