USB Type-A charge port converter includes a synchronous DC-DC converter

19-11-2019 | Texas Instruments | Power

Texas Instruments TPS2584x-Q1 USB Type-A Charge Port Converter is a BC1.2 charging solution that incorporates a synchronous DC-DC converter. With cable droop compensation, the VBUS voltage remains constant no matter the load current. This guarantees that ensuring connected portable devices are charged at optimal current and voltage even if under heavy loads. The device comprises high bandwidth analog switches for DP and DM pass-through. The device also incorporates short to battery protection on VBUS, DM_IN, and DP_IN pins. These pins can resist a voltage up to 18V, while the converter does not support data line (Dx) short to VBAT protection.

The synchronous buck regulator works with current-mode control and is internally compensated to simplify the design. A resistor on the RT pin sets the switching frequency within 300kHz and 2.2MHz. It runs below 400kHz results in better system efficiency. Operation above 2.1MHz bypasses the AM radio bands and provides for the employment of a smaller inductor. The device incorporates electrical signatures necessary for legacy devices that employ USB data lines to ascertain the charging configuration.

A precision current sense amplifier is incorporated for user-programmable cable droop compensation and current limit tuning. Cable compensation assists portable devices in charging at optimum current and voltage under heavy loads. This is accomplished by adjusting the buck regulator output voltage linearly with load current to offset the voltage drop due to wire resistance in automotive cabling. The VBUS voltage measured at a connected portable device continues approximately constant, despite load current, enabling the portable device’s battery charger to work optimally.

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