REFERENCE VOLTAGE GENERATING CIRCUIT AND TIMER CIRCUIT
A reference voltage generating circuit includes a constant current source circuit connected with a power supply voltage and configured to output a reference current to an output node based on the power supply voltage. A current-voltage converting circuit is connected the output node and generates a reference voltage to the output node based on the reference current. A first voltage adjusting circuit is connected with the output node and is configured to adjust dependence of the reference voltage on the power supply voltage in a positive direction. A second voltage adjusting circuit is connected with the output node and is configured to adjust dependence of the reference voltage on the power supply voltage in a negative direction.
1 . A reference voltage generating circuit comprising:
a constant current source circuit connected with a power supply voltage and configured to output a reference current to an output node based on the power supply voltage;
a current-voltage converting circuit connected said output node and configured to generate a reference voltage to said output node based on the reference current;
a first voltage adjusting circuit connected with said output node and configured to adjust dependence of said reference voltage on the power supply voltage in a positive direction; and
a second voltage adjusting circuit connected with said output node and configured to adjust dependence of said reference voltage on the power supply voltage in a negative direction.
2 . The reference voltage generating circuit according to claim 1 , wherein said first voltage adjusting circuit is connected with said output node to supply a first current to said current-voltage converting circuit.
3 . The reference voltage generating circuit according to claim 2 , wherein said first voltage adjusting circuit comprises:
a first resistance element connected between said power supply voltage and said output node, and
said first current is supplied to said output node via said first resistance element.
4 . The reference voltage generating circuit according to claim 1 , wherein said first voltage adjusting circuit adjusts the dependence of said reference voltage on the power supply voltage in the positive direction when the reference current has dependence on the power supply voltage.
5 . The reference voltage generating circuit according to claim 1 , wherein said second voltage adjusting circuit is connected with said output node to shunt the second current from the reference current.
6 . The reference voltage generating circuit according to claim 5 , wherein said second voltage adjusting circuit comprises:
a second resistance element provided between said power supply voltage and a ground voltage, and
said second voltage adjusting circuit shunts the second current based on a current flowing through said second resistance element.
7 . The reference voltage generating circuit according to claim 1 , wherein said second voltage adjusting circuit adjusts the dependence of the reference voltage on the power supply voltage when the reference current has a dependence on the power supply voltage.
8 The reference voltage generating circuit according to claim 1 , wherein said first voltage adjusting circuit has a first switch,
said second voltage adjusting circuit has a second switch,
said first voltage adjusting circuit adjusts the dependence of the reference voltage on the power supply voltage when said first switch is turned on, and
said second voltage adjusting circuit adjusts the dependence of the reference voltage on the power supply voltage when said second switch is turned on.
9 . The reference voltage generating circuit according to claim 1 , wherein said current-voltage converting circuit generates the reference voltage based on a current supplied from said constant current circuit.
10 . The reference voltage generating circuit according to claim 1 , wherein said current-voltage converting circuit comprises:
a third resistance element and a first diode of a forward direction which are connected in series between said output node and the ground voltage.
11 . The reference voltage generating circuit according to claim 1 , wherein said current-voltage converting circuit comprises:
a transistor having a drain and a gate connected with said output node; and
a fourth resistance element connected between a source of said transistor and the ground voltage.
12 . A timer circuit comprising:
a reference voltage generating circuit configured to output a reference voltage; and
a ring oscillator section including a current control type ring oscillator circuit,
wherein a current quantity supplied to said current control type ring oscillator circuit is determined based on the reference voltage, and
said reference voltage generating circuit comprises:
a constant current source circuit connected with a power supply voltage and configured to output a reference current to an output node based on the power supply voltage;
a current-voltage converting circuit connected said output node and configured to generate a reference voltage to said output node based on the reference current;
a first voltage adjusting circuit connected with said output node and configured to adjust dependence of said reference voltage on the power supply voltage in a positive direction; and
a second voltage adjusting circuit connected with said output node and configured to adjust dependence of said reference voltage on the power supply voltage in a negative direction.
13 . The timer circuit according to claim 12 , further a second diode element,
wherein the current quantity supplied to said current control type ring oscillator circuit depends on said second diode element in addition to the reference voltage.