A constant current circuit is provided including: a constant current generation circuit; a control transistor included in the constant current generation circuit and configured to flow with a constant current generated by the constant current generation circuit and with a start-up current at start-up; an output transistor having a gate voltage controlled by the control transistor and configured to generate an output current based on the constant current; and a bypass transistor having a gate with common connection to a gate of the control transistor and configured to cause the start-up current flowing in the control transistor to bypass after start-up.

A tracking voltage generator, the latter including: a first transistor having a first leakage current and which is coupled with the flipped gate transistor so that a difference between a gate-source voltage (Vgs) of a flipped gate transistor and the first transistor is approximately equal to a bandgap voltage of a semiconductor material from which the tracking voltage generator is formed; an output node providing a tracking voltage which has a positive or negative temperature dependency based on the flipped gate transistor and the first transistor; and a second transistor connected to the output node and which has a second leakage current. A current reference includes: the tracking voltage generator; an amplifier to receive the tracking voltage and output an amplified signal; a control transistor to receive the amplified signal and conduct a reference current therethrough; and a control resistor connected in series with the control transistor.

The constant current circuit includes a constant current generation circuit, a start-up detection circuit configured to detect start-up of the constant current generation circuit, and a clamp circuit configured to output a start-up voltage to the constant current generation circuit. The start-up voltage output from the clamp circuit is a voltage close to gate voltages that are higher than gate voltages of transistors that form a current mirror circuit of the constant current generation circuit, in a state where the constant current generation circuit is operating.

A power supply circuit that outputs via an output terminal an output voltage based on an input voltage applied to an input terminal includes: an inserted transistor of an N-channel depletion type inserted between the input terminal and an internal supply power terminal; and a regulator configured to generate the output voltage by using as a supply voltage a voltage applied to the internal supply power terminal. The gate of the inserted transistor is connected to the output terminal.

An apparatus is provided which generates a reverse bandgap reference using capacitive bias, which is applied to a single n-well diode. The capacitive bias allows for determining the current density precisely by pure timing control. An apparatus is also described for sensing temperature in which a forward-bias diode voltage can be sampled with a capacitor, and large current ratios are possible (e.g., ratio N greater than 1000). Duty cycle of a digital output of the sensor is used to determine the temperature sensed by the sensor.

Provided is a reference voltage circuit including a Zener diode having a cathode connected to a current source via a first node, and an anode connected to a ground point; a first resistor having one end connected to the first node; a second resistor having one end connected to another end of the first resistor; a first diode having an anode connected to another end of the second resistor via a second node, and a cathode connected to the ground point; and a current control circuit configured to generate a control current corresponding to an anode voltage of the first diode so that the current source supplies a reference current corresponding to the control current to the first diode.

A monostable circuit includes a delay cell with a reference generator generating a reference current based upon a PVT invariant resistance and a threshold voltage, and a delay block with an output capacitor and an output circuit altering an amount of charge stored on the output capacitor as a function of the reference current, in response to an input signal. An inverter has an input coupled to the output circuit. A logic circuit logically combines output of the inverter and the input signal to generate a monostable trigger pulse. The output circuit includes a current source sourcing the reference current to the output capacitor in response to a first logic state of an input signal, and a current sink sinking current from the output capacitor to discharge the output capacitor, in response to a second logic state of the input signal.

A controllable temperature coefficient bias (CTCB) circuit is disclosed. The CTCB circuit can provide a bias to an amplifier. The CTCB circuit includes a variable with temperature (VWT) circuit having a reference circuit and a control circuit. The control circuit has a control output, a first current control element and a second current control element. Each current control element has a controllable resistance. One of the two current control elements may have a relatively high temperature coefficient and another a relatively low temperature coefficient. A controllable resistance of one of the current control elements increases when the controllable resistance of the other current control element decreases. However, the total resistance of the current control circuit remains constant with a constant temperature. The VWT circuit has an output with a temperature coefficient that is determined by the relative amount of current that flows through each current control element of the control circuit. A Current Digital to Analog Converter (IDAC) scales the output of the VWT and provides the scaled output to an amplifier bias input.

A watch is provided that includes a constant current circuit including: a plurality of transistors coupled in series between a first power supply and a second power supply, the first power supply being a power supply of a high potential side power supply, the second power supply being a power supply of a low potential side power supply; a plurality of connection wiring lines each provided for each of the plurality of transistors, and configured to couple the first power supply and a terminal on the first power supply side of each of the plurality of transistors; a non-disconnected fuse provided in a non-disconnected state to one connection wiring line of the plurality of connection wiring lines, and a disconnected fuse provided in a disconnected state to a connection wiring line other than the one connection wiring line of the plurality of connection wiring lines.

A voltage reference circuit includes a first circuit block configured to generate a proportional to absolute temperature current, the first circuit block comprising a current mirror amplifier, a second circuit block coupled to the first circuit block and configured to generated a complimentary to absolute temperature current, and a third circuit block coupled to both the first circuit block and the second circuit block. The second circuit block includes a multi-stage common-source amplifier. The third circuit block is configured to combine the proportional to absolute temperature current and the complimentary to absolute temperature current to generate a reference voltage at an output of the voltage reference circuit.