Reversible buck or boost converter that determines boost output current from sensed boost input current

A method comprising:

• operating an integrated circuit in a buck mode and in a boost mode, wherein the integrated circuit includes a first terminal VIN, a second terminal SW, a third terminal CSP, a fourth terminal CSM, a fifth terminal VOUT, a sixth terminal PGND, a first switch and a second switch;
• receiving a supply voltage onto the first terminal VIN in the buck mode;
• supplying a charging current into a battery in the buck mode, wherein the charging current flows out of the integrated circuit from the second terminal SW, through an inductor, through a current sense resistor, and into the battery, wherein the current sense resistor is coupled between the third terminal CSP and the fourth terminal CSM, and wherein the current sense resistor, the inductor, and the battery are external to the integrated circuit;
• and
• controlling a magnitude of the charging current flowing into the battery in the buck mode using the current sense resistor.

An integrated circuit comprising:

• a first terminal;
• a second terminal;
• a third terminal;
• a fourth terminal;
• a fifth terminal;
• a sixth terminal;
• a first switch connected directly between the fifth terminal and the second terminal;
• a second switch connected directly between the second terminal and the sixth terminal;
• and
• means for controlling the first and second switches in a buck mode such that a first current flows in a first current path out of the integrated circuit from the second terminal, through an inductor, through a current sense resistor, and into a battery thereby charging the battery, wherein the current sense resistor is coupled between the third and fourth terminals, wherein an output capacitor is coupled between the fifth and sixth terminals, wherein the means controls a magnitude of the first current in the buck mode at least in part by detecting a magnitude of the first current as a voltage drop across the current sense resistor, and wherein the inductor, the current sense resistor, the battery and the output capacitor are external to the integrated circuit.