Two Channel High-Side Switch with Current Sensing

This is a two Channel high-side switch designed for automotive applications. It has a built-in overcurrent limit function, thermal shutdown protection function, open load detection function, low power output-OFF function etc. It also has a current sensing function of output load current.

• Resistor R1, R2, R6, R7 limit resistance for the negative surge
• Resistor R3, R8, capacitor C2, C4 for noise suppression filters

Features

• Power 6V to 28V DC
• ON Resistance 45mOhmes
• Built-in current sensing function
• Built-in Dual TSD (Note 1)
• Built-in Overcurrent Protection Function (OCP)
• Built-in thermal shutdown protection function (TSD)
• Built-in open load detection function
• Built-in Low-Voltage Output-OFF Function (UVLO)
• Built-in diagnostic output
• Input Frequency 1Khz
• Low On-Resistance Single Nch MOSFET Switch (On Resistance 45mOhm)
• Screw Terminals for Loads and Power Input
• Header Connector for Input, Current Sense
• 4 x 4 mm Mounting Holes
• PCB Dimensions 54.61 x 40.32 mm

The sense voltage varies linearly according to the load current IOUT during normal operation The Vsense theoretical equation are shown bellow:

• Vsense=Rsense/Isense
• Isense=Iout/N
• Vsense=RsenseXIout/N= 1000X2/1450 = 1.379V
• Vsense=1.379V/2A

Connections

• CN1: Pin 1 = VI1 Load Supply, Pin 2 = GND
• CN3: Pin 1 = Load/OP1, Pin 2 = GND
• CN4: Pin 1 = VI2 Load Supply, Pin 2 = GND
• CN5: Pin 1 = Load/OP2, Pin 2 = GND
• D1: Output 1 LED
• D2: Output 2 LED
• CN2: Pin 1 = Input 1, Pin 2 = Diagnostic/Sense/Enable 1, Pin 3 = Sense 1, Pin 4 = GND, Pin 5 = Input 2,Pin 6 = Diagnostic/Sense/Enable 2, Pin 7 =- Sense 2, Pin 8 = GND

Inrush Current When power is first supplied to the IC, it is possible that the internal logic may be unstable and inrush current may flow instantaneously due to the internal powering sequence and delays, especially if the IC has more than one power supply. Therefore, give special consideration to power coupling capacitance, power wiring, width of ground wiring, and routing of connections.

Thermal Shutdown Function (TSD) This IC has a built-in thermal shutdown function that prevents heat damage to the IC. Normal operation should always be within the IC’s maximum junction temperature rating. If however, the rating is exceeded for a continued period, the junction temperature (Tj) will rise which will activate the TSD function that will turn OFF power output pins. When the Tj falls below the TSD threshold, the circuits are automatically restored to normal operation. Note that the TSD function operates in a situation that exceeds the absolute maximum ratings and therefore, under no circumstances, should the TSD function be used in a set design or for any purpose other than protecting the IC from heat damage.

Thermal Shutdown Protection This IC has a built-in thermal shutdown protection function. When the IC chip temperature exceeds175 °C (Typ), the output is turned OFF and self-diagnostic output (SENSE) becomes VSENSEH. When the temperature goes below 150 °C (Typ), output will self-reset and operation becomes normal.

ΔTj Protection This IC has a built-in ΔTj protection function that turns OFF the output when the temperature difference (TDTJ) between the POWER-MOS unit (TPOWER-MOS) and the control unit (TAMB) in the IC is 90 °C (Typ) or more. ΔTj protection also has a built-in hysteresis (TDTJHYS) that returns the output to normal state when the temperature difference becomes 30 °C (Typ) or less.

Over Current Protection Function This IC incorporates an integrated overcurrent protection function that is activated when the load is shorted. This protection function is effective in preventing damage due to sudden and unexpected incidents. However, the IC should not be used in applications characterized by continuous operation or transitioning of the protection function. When overcurrent flows in the output, the output current is limited to 30A (Typ) and self-diagnostic output (SENSE) becomes VSENSEH.