Voltage regulator with control of the feedback voltage divider
A voltage regulator includes a voltage generator configured to receive a reference voltage and a feedback voltage and configured to generate an output voltage corresponding to the feedback voltage, a voltage divider configured to divide the output voltage to generate the feedback voltage, and a controller configured to control a voltage division value of the voltage divider in response to a program enable signal and a charge-pump enable signal during an activation period of an enable signal.
1. A voltage regulator comprising:
a voltage generator configured to receive a reference voltage and a feedback voltage and configured to generate an output voltage corresponding to the feedback voltage;
a voltage divider configured to divide the output voltage to generate the feedback voltage; and
a controller configured to control a voltage division value of the voltage divider in response to a program enable signal and a charge-pump enable signal during an activation period of an enable signal
wherein:
during a predetermined period after activating the program enable signal, a resistance value of the voltage divider is adjusted in response to an output of the controller, and the feedback voltage is changed in response to the adjusted resistance value so that the output voltage increases to a predetermined target level or higher.
2. The voltage regulator according to claim 1 , wherein the voltage generator includes:
an amplifier configured to compare the reference voltage with the feedback voltage, amplify a voltage based on a difference between the reference voltage and the feedback voltage, and output the amplified voltage;
a buffer configured to supply a driving voltage in response to the amplified voltage; and
a driver configured to adjust a level of the output voltage in response to the driving voltage.
3. The voltage regulator according to claim 1 , wherein the voltage divider includes:
a plurality of resistors connected in series between an output terminal of the output voltage and a ground voltage terminal.
4. The voltage regulator according to claim 1 , wherein the controller is configured to:
generate a control signal to be activated for a predetermined period in response to the program enable signal and the charge-pump enable signal, and
change a resistance value of the voltage divider in response to the control signal.
5. The voltage regulator according to claim 1 , wherein the controller includes:
a voltage controller configured to generate a control signal for controlling the voltage division value of the voltage divider in response to the program enable signal and the charge-pump enable signal during the activation period of the enable signal; and
a switching circuit configured to adjust a resistance value of the voltage divider in response to the control signal.
6. The voltage regulator according to claim 5 , wherein the voltage controller includes:
a rising delay circuit configured to generate a rising delay signal by delaying a rising edge signal of the charge-pump enable signal;
a selector configured to select any one of the program enable signal and the rising delay signal in response to the charge-pump enable signal and configured to output the selected signal as a pulse input signal;
a pulse generator configured to generate a pulse signal in response to the pulse input signal;
a delay circuit configured to generate a delay signal by delaying the program enable signal for a predetermined time; and
a control signal generator configured to generate the control signal in response to the enable signal, the program enable signal, the delay signal, and the pulse signal.
7. The voltage regulator according to claim 6 , wherein the selector is configured to:
output the program enable signal as the pulse input signal when the charge-pump enable signal is deactivated; and
output the rising delay signal as the pulse input signal when the charge-pump enable signal is activated.
8. The voltage regulator according to claim 6 , wherein:
the pulse generator is configured to generate the pulse signal in the form of a one-shot pulse signal having a constant pulse width in synchronization with a rising edge of the pulse input signal.
9. The voltage regulator according to claim 6 , wherein the control signal generator is configured to:
activate the control signal in synchronization with a first activation time point of the pulse signal; and
deactivate the control signal in synchronization with a second activation time point of the pulse signal.
10. The voltage regulator according to claim 6 , wherein:
the control signal is activated for a predetermined period from a time point at which the program enable signal is activated and remains activated until the rising delay signal is activated from a time point at which the charge-pump enable signal is activated.
11. The voltage regulator according to claim 5 ,
wherein the voltage divider includes:
a first resistor connected between an output terminal of the output voltage and a first node; and
a second resistor connected between the first node and a second node, and
wherein the switching circuit includes:
a transistor configured to include a first terminal connected to the first node and a second terminal connected to the second node so that a switching operation is controlled by the control signal.
12. The voltage regulator according to claim 11 , wherein the voltage divider is configured to:
determine the voltage division value in response to the first resistor and the second resistor when the transistor is turned off by deactivating the control signal; and
determine the voltage division value in response to the first resistor when the transistor is turned on by activating the control signal.
13. The voltage regulator according to claim 1 , wherein:
the program enable signal and the charge-pump enable signal are activated in a program mode of a load to which the output voltage is supplied; and
after a predetermined time elapses from a time point at which the program enable signal is activated in the activation period of the enable signal, the charge-pump enable signal is activated.
14. A voltage regulator comprising:
a voltage generator configured to receive a reference voltage and a feedback voltage and configured to generate an output voltage corresponding to the feedback voltage;
a voltage divider configured to divide the output voltage to generate the feedback voltage; and
a controller configured to control a voltage division value of the voltage divider in response to a program enable signal and a charge-pump enable signal during an activation period of an enable signal,
wherein the feedback voltage is changed according to the voltage division value so that the output voltage increases to a predetermined target level or higher during a first period and then sequentially decreases during a second period after the first period elapses.
15. The voltage regulator according to claim 14 , wherein:
the program enable signal and the charge-pump enable signal are activated in a program mode of a load to which the output voltage is supplied; and
after a predetermined time elapses from a time point at which the program enable signal is activated in the activation period of the enable signal, the charge-pump enable signal is activated.
16. The voltage regulator according to claim 14 , wherein the voltage generator includes:
an amplifier configured to compare the reference voltage with the feedback voltage, amplify a voltage based on difference between the reference voltage and the feedback voltage, and output the amplified voltage;
a buffer configured to supply a driving voltage in response to the amplified voltage; and
a driver configured to adjust a level of the output voltage in response to the driving voltage.
17. The voltage regulator according to claim 14 , wherein the controller includes:
a voltage controller configured to generate a plurality of control signals for controlling the voltage division value of the voltage divider in response to the program enable signal and the charge-pump enable signal during the activation period of the enable signal; and
a switching circuit configured to adjust a resistance value of the voltage divider in response to the plurality of control signals.
18. The voltage regulator according to claim 17 , wherein the voltage controller includes:
a plurality of rising delay circuits configured to respectively generate a plurality of rising delay signals having different delay times by delaying a rising edge signal of the charge-pump enable signal;
a plurality of selectors configured to select any one of the program enable signal and the plurality of rising delay signals in response to the charge-pump enable signal and configured to respectively output a plurality of pulse input signals;
a plurality of pulse generators configured to respectively generate a plurality of pulse signals in response to the plurality of pulse input signals;
a delay circuit configured to generate a delay signal by delaying the program enable signal for a predetermined time; and
a control signal generator configured to generate the plurality of control signals in response to the enable signal, the program enable signal, the delay signal, and the plurality of pulse signals.
19. The voltage regulator according to claim 17 , wherein:
the voltage divider includes a plurality of resistors connected in series between an output terminal of the output voltage and a ground voltage terminal, and
the switching circuit includes a plurality of switching elements respectively connected in parallel to some of the plurality of resistors so that switching operations of the switching elements are controlled by the plurality of control signals,
wherein, after a predetermined delay time elapses from a time point at which the charge-pump enable signal is activated, the plurality of switching elements is sequentially turned off in response to the plurality of control signals.