Single-Channel Smart High-Side Power Switch with Programmable Current Limit

This is a single-channel, fully-protected, high-side power switch with programmable current-limit. 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. 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 the Vs active drain and a 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 (EBAT) and the load (ELOAD) are dissipated on the high-side power switch itself. With the benefits of process technology and excellent IC layout, the TPS1H100BQ-Q1 device can achieve excellent power dissipation capacity. When a fault condition occurs, CS works as a diagnostics report pin. When an open load or short to battery occurs in the on-state, VCS almost equals 0. When the current limit, thermal shutdown/swing, open load, or short to battery in the off-state occurs, the voltage is pulled up to VCS.

The project can be used as a high-side power switch for a wide variety of resistive, inductive, and capacitive loads, including low-wattage bulbs, LEDs, relays, solenoids, and heaters. CL (Current Limit) resistor can be changed through PR1 Trimmer potentiometer. When PR1 is 0 Ohm there is no external current limit function and the internal current limit is active. This current limit value is around 0.5A.

Features

• Operating voltage 5 to 37V (Limited Due to L317 Input Supply)
• Current Limit Adjustable 0.5A to 5Amps (PR1 Trimmer Potentiometer)
• Operating junction temperature: –40ºC to 150ºC
• Very-low standby current: <1 µA
• Microcontroller input control: 3.3-V and 5-V logic compatible
• High-accuracy current sense – Analog current output as a ratio of the output current (3% at nominal load and 20% at light load)
• Programmable current limit with external Trimmer Potentiometer PR1
• High-accuracy current sense, ±30 mA at 1 A, ±4 mA at 5 mA
• PCB Dimensions 73.50 x 39.05 mm
• 4 x 3 mm Mounting Holes
• Protection:
  • Short-circuit protection
  • Overvoltage protection,
  • Thermal shutdown/swing with self-recovery
  • Loss of GND,
  • loss of Vs protection– ESD protection
• Diagnostic:
  • On/off state output open/short to battery detection
  • Overload and short-to-ground detection and power limiting
  • Thermal shutdown/swing diagnostic
  • Current-sense analog diagnostic
  • Diagnostic enable function for multiplexing of MCU analog or digital port