Abstract
The present invention discloses an offset cancellation current mirror and method thereof. The offset cancellation current mirror comprises a first current mirror, a second current mirror, switches and resistant. The first current mirror comprises two transistors and a capacitance, the capacitance is used to store a electrical potential difference when the switches is turned on in ways of connecting the first current mirror with the resistant. When the switches is turned off in ways of disconnecting the first current mirror with the resistant and connecting the first current mirror with the second current mirror, the electrical potential difference stored in the capacitance is used to correct the difference of the two transistors due to manufacture process.