IR2 103 is a half-bridge driver, and it can also be driven by two H-bridges.

HIN input high level HO output high level, but this level is relative to Vs;

LIN inputs low level LO and outputs low level, but this level is relative to COM.

Bootstrap capacitor is used to provide high-end driving power supply VB: the high-end driving output TC(Vs) oscillates at high frequency, which is the high-voltage terminal voltage when the upper tube is turned on and the ground level when the lower tube is turned on. When TC is at ground level, Vcc charges the bootstrap capacitor to a voltage close to Vcc through a diode, and Vcc supplies power to VB. When TC is at high level, the diode is turned off, and the bootstrap capacitor is discharged to supply power to VB. Bootstrap capacitor can only work when it oscillates at high frequency.

Its Chinese information can be found at/IRF/IR2103/1.html.