Over-Current Sensing IC
IR's patented high voltage IC technology enables smaller circuit size and reduces component count and cost. Typical applications include light industrial AC and brushless DC motor drives, and appliance applications such as washing machines and air conditioners.
The device includes a 1.5 microsecond over-current shutdown that works with a wired-OR connection directly to the microcontroller or DSP. Motor current in both positive and negative directions are sensed by the unit so that both IGBT and diode over-current conditions are reported. Conventional linear current-sensing optical- or Hall effect-based systems have typical shutdown times of three to four microseconds. Motor drive circuits using opto- or Hall-effect sensors require two external comparators and a level-shift operational amplifier to achieve the same function.
The device requires one milliamp (1mA) quiescent current and an input supply voltage range of 7 to 20V. Sharing the bootstrap supplies with the HVIC gate driver eliminates the need for separate, isolated supplies. Internal filtering and high speed transient response time eliminates false alarms often generated by competing over current protection solutions.
The new over-current protection IC comes in either SO-8 or 8-pin DIP. The IR2170 is the latest addition to the IR217x family of integrated, high voltage current-sensing and protection ICs. Other devices in the family include the IR2171 which sends a linear current sense output signal in PWM format and the IR2172 which combines the functions of the IR2170 and IR2171.
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