TIPD103

This Verified Design circuit is a bidirectional current source that can be used to drive floating loads, specifically thermo-electric coolers (TECs) from a single-ended source. The circuit makes use of an internal output current monitor circuit (IMON), which is a special feature of the OPA569 power amplifier. The V-I transfer function is accomplished by using the IMON current as the feedback for the first amplifier. This enables the user to create an input signal that cancels the IMON current to achieve a well regulated output current. The second amplifier inverts the output of the first amp to achieve the bridge tied load (BTL) operation, doubling the voltage swing and slew rate across the load, allowing for bidirectional operation and good voltage swing on the single-ended power supply. The excellent output swing-to-rail of the OPA569 allows for 4.5 V of usable output voltage at 2 A output current with a 5 V single-ended power supply.

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