The invention discloses an integrated converter circuit used for optical energy collection. The converter circuit has a maximum power point tracking function and is applicable for small wearable equipment for low energy harvesting. The integrated converter circuit comprises a power level module, a voltage sampling module, a current sampling module, an analog multiplier, a sampling and holding circuit, a dynamic comparer, a dithered digital pulse width modulation (DDPWM) module, a driver and an oscillator module. The DDPWM module is used for dithering on the duty ratio signal of a control power tube according to a designed dithering sequence; the voltage sampling module and the current sampling module are used for sampling the output voltage and current of a photovoltaic cell respectively and inputting the output voltage and current into the analog multiplier; the sampling and holding circuit is used for sampling the output of the analog multiplier at two specific moments under the control of a sequence signal and using the dynamic comparer to compare the output of the analog multiplier at two specific moments; and duty ratio control signal of the power tube is increased or decreased according to the output result of the dynamic comparer so that the dynamic tracking of the maximum power point is realized.