7.1 Overview

The TPS1H100-Q1 is a single-channel, fully-protected, high-side power switch with an integrated NMOS power FET and charge pump. Full diagnostics and high-accuracy current-sense features enable intelligent control of the load. A programmable current-limit function greatly improves the reliability of the whole system. The device diagnostic reporting has two versions to support both digital status and analog current-sense output, both of which can be set to the high-impedance state when diagnostics are disabled, for multiplexing the MCU analog or digital interface among devices.

For version A, the digital status report is implemented with an open-drain structure. When a fault condition occurs, it pulls down to GND. A 3.3- or 5-V external pullup is required to match the microcontroller supply level. For version B, high-accuracy current sensing allows a better real-time monitoring effect and more-accurate diagnostics without further calibration. A current mirror is used to source 1 / K of the load current, which is reflected as voltage on the CS pin. K is a constant value across the temperature and supply voltage. The current-sensing function operates normally within a wide linear region from 0 to 4 V. The CS pin can also report a fault by pulling up the voltage of V_CS,h.

The external high-accuracy current limit allows setting the current limit value by application. It highly improves the reliability of the system by clamping the inrush current effectively under start-up or short-circuit conditions. Also, it can save system costs by reducing PCB trace, connector size, and the preceding power-stage capacity. An internal current limit is also implemented in this device. The lower value of the external or internal current-limit value is applied.

An active drain and source voltage clamp is built in to address switching off the energy of inductive loads, such as relays, solenoids, pumps, motors, and so forth. During the inductive switching-off cycle, both the energy of the power supply (E_BAT) and the load (E_LOAD) are dissipated on the high-side power switch itself. With the benefits of process technology and excellent IC layout, the TPS1H100-Q1 device can achieve excellent power dissipation capacity, which can help save the external free-wheeling circuitry in most cases. See Inductive-Load Switching-Off Clamp for more details.

Short-circuit reliability is critical for smart high-side power-switch devices. The standard of AEC-Q100-012 is to determine the reliability of the devices when operating in a continuous short-circuit condition. Different grade levels are specified according to the pass cycles. This device is qualified with the highest level, Grade A, 1 million times short-to-GND certification.

The TPS1H100-Q1 device can be used as a high-side power switch for a wide variety of resistive, inductive, and capacitive loads, including the low-wattage bulbs, LEDs, relays, solenoids, and heaters.