US Patent 11467463 Overcharge-aware driver for electrochromic devices

A overcharge-aware electrochromic device driver for preventing overcharge of an electrochromic device is described. One driver applies a constant supply current to an electrochromic device from a power supply. The driver determines an amount of charge as a function of time and current supplied to the electrochromic device. The driver determines whether the amount of charge reaches an overcharge limit before a sense voltage reaches a first sense voltage limit. Responsive to the amount of charge reaching the overcharge limit, the driver sets the sense voltage as a second sense voltage limit that is lower than the first sense voltage limit, ceases the constant supply current, and applies one of a variable voltage or a variable current to the electrochromic device from the power supply to maintain the sense voltage at the second sense voltage limit.