Patent ID: 7468620

Claim:
A frequency generator apparatus, comprising: a control circuit, includina an electric fuse (efuse) and outputting an enabling signal according to the state of the efuse; and a frequency generator, coupled to the control circuit to receive the enabling signal and decide whether to output a frequency signal or not according to the enabling signal, wherein the control circuit comprises: the efuse, with a first end coupled to a programming node; a first switch, having a first end, a second end, and a control end, with the first end coupled to the first end of the efuse, with the second end being grounded, and with the control end used for receiving a first control signal to decide whether to turn on the first switch or not according to the first control signal; a first impedance, with a first end coupled to a first voltage; a second impedance, with a first end coupled to the first voltage; a current mirror device, having a first end, a second end, a third end, and a fourth end, with the first end coupled to the second end of the first impedance, with the second end coupled to the second end of the second impedance, wherein the current mirror device decides the current value of the second and fourth ends according to the current passing through the first and third ends, and the second end of the current mirror device outputs the enabling signal; a second switch, having a first end, a second end, and a control end, with the first end coupled to the third end of the current mirror device, and with the control end used for receiving the first control signal to decide whether to turn on the second switch or not according to the first control signal; a third switch, having a first end, a second end, and a control end, with the first end coupled to the fourth end of the current mirror device, with the second end coupled to the second end of the efuse, and with the control end used for receiving the first control signal to decide whether to turn on the third switch or not according to the first control signal; a fourth switch, having a first end, a second end, and a control end, with the first end coupled to the second end of the second switch, with the second end being grounded, and with the control end used for receiving the first control signal to decide whether to turn on the fourth switch or not according to the first control signal; and a fifth switch, having a first end, a second end, and a control end, with the first end coupled to the second end of the third switch, with the second end being grounded, and with the control end used for receiving a second control signal to decide whether to turn on the fifth switch ot not according to the second control signal.