Signal calculator
Examples of a signal calculator include a voltage multiplier and a time divider. The voltage multiplier copies time information corresponding to a first voltage and generates a third voltage using a second current corresponding to a second voltage during a first period corresponding to the copied time information. The time divider generates an output according to a result of comparing a voltage generated by a first current on the basis of a voltage corresponding to a first time with a second voltage corresponding to a second time.
1. A voltage multiplier comprising:
a first capacitor;
a first comparator configured to generate time information according to a result of comparing a first voltage with a voltage charged in the first capacitor by a first current;
a time copier configured to copy the time information; and
a current generator configured to generate a second current corresponding to a second voltage,
wherein a third voltage is charged in the first capacitor by the second current during a first period corresponding to the copied time information.
2. The voltage multiplier of claim 1 , wherein the time copier copies the time information based on a result of comparing a fourth voltage, which is a sample of a voltage charged in a second capacitor during a period corresponding to the time information, with a fifth voltage charged in the second capacitor by a third current.
3. The voltage multiplier of claim 2 , wherein the time copier comprises:
a first switch including one end coupled to one end of the second capacitor and which is turned on during the period corresponding to the time information;
a second switch including one end coupled to the one end of the second capacitor and which is turned on during a predetermined second period after the fourth voltage is sampled; and
a third switch coupled in parallel to both ends of the second capacitor,
wherein the third switch is turned on at a first time point between a time point at which the fourth voltage is sampled and a starting time point of the second period and at a second time point after an end time point of the second period.
4. The voltage multiplier of claim 3 , wherein the time copier further comprises:
a fourth switch including one end electrically coupled to the one end of the second capacitor and which is turned on to sample the fourth voltage; and
a third capacitor coupled to the other end of the fourth switch.
5. The voltage multiplier of claim 4 , wherein the time copier further comprises:
a fifth switch including one end electrically coupled to the one end of the second capacitor and which is turned on during the second period; and
a second comparator which includes a first input terminal coupled to the third capacitor and a second input terminal coupled to the other end of the fifth switch, and which outputs a result of comparing an input to the first input terminal with an input to the second input terminal.
6. The voltage multiplier of claim 5 , further comprising a logic operation part configured to generate the copied time information based on an output of the second comparator during the second period.
7. The voltage multiplier of claim 3 , wherein the time copier further includes a current source coupled to the other end of the first switch and the other end of the second switch and configured to supply the third current.
8. The voltage multiplier of claim 3 , wherein the time copier further comprises a resistance including one end coupled to the other end of the first switch and the other end of the second switch and the other end to which a predetermined voltage is supplied.
9. The voltage multiplier of claim 1 , further comprising:
a first switch including one end coupled to one end of the first capacitor and which is turned on during the first period;
wherein the current generator is coupled to the other end of the first switch and configured to generate the second current by copying a current determined according to the second voltage.
10. The voltage multiplier of claim 9 , wherein the current generator comprises:
a transistor;
a resistance coupled to one end of the transistor;
an error amplifier including an output terminal coupled to a gate of the transistor, a first input terminal to which the second voltage is input, and a second input terminal coupled to the one end of the transistor;
a current mirror coupled to the other end of the transistor and configured to copy a current flowing in the transistor; and
a current source configured to generate the second current according to a current transmitted from the current mirror.