Voltage modulator

Patent metadata

Field	Value
Publication number	US-9634560-B2
Application number	US-201414779108-A
Country	US
Kind code	B2
Filing date	Feb 11, 2014
Priority date	Mar 26, 2013
Publication date	Apr 25, 2017
Grant date	Apr 25, 2017

Abstract

A voltage modulator ( 400 ) comprises a multi-level switched capacitor modulator ( 44 ) connected in parallel with a switched voltage regulator ( 42 ). An output of the multi-level switched capacitor modulator and an output of the switched voltage regulator are combined, or both connected to an output node, to generate an output voltage. The voltage modulator has an input node to receive at least one input signal and further comprises a control unit ( 46 ) arranged to control the switched voltage regulator and the multi-level switched capacitor modulator such that the output voltage follows the input signal.

First claim

The invention claimed is:

1. A voltage modulator, comprising:
a multi-level switched capacitor modulator;
a switched voltage regulator;
an input node to receive an input signal and an output node to output a voltage;
wherein an output of the multi-level switched capacitor modulator and an output of the switched voltage regulator are both connected to the output node of the voltage modulator; and
a control circuit configured to control the switched voltage regulator and the multi-level switched capacitor modulator such that the output voltage follows the input signal.

2. The voltage modulator of claim 1 :
wherein the multi-level switched capacitor modulator comprises a storage capacitor; and
wherein the storage capacitor is configured to be:
charged when an output current is smaller than a current delivered by the switched voltage regulator; and
discharged when the output current is larger than the current delivered by the switched voltage regulator.

3. The voltage modulator of claim 2 , wherein the control circuit comprises a first control loop configured to control switches of the switched voltage regulator such that voltage stored in the storage capacitor reaches a value set by a control signal.

4. The voltage modulator of claim 3 , wherein the first control loop is configurable to operate at different bandwidths in different operation modes.

5. The voltage modulator of claim 3 , wherein the first control loop comprises:
a first error amplifier configured to:
receive a voltage signal from the storage capacitor and the control signal; and
output an error signal representing a difference between the voltage signal and the control signal;

a comparator configured to receive the error signal generated by the first error amplifier and a saw tooth signal to generate a pulse width modulation signal; and
a switch control signal generator configured to generate switch control signals to the switched voltage regulator based on the pulse width modulation signal generated by the comparator of the first control loop.

6. The voltage modulator of claim 5 , wherein the switch control signal generator of the first control loop comprises inverters and delay stages configured to tune switching instants such that non-overlapping switching is achieved.

7. The voltage modulator of claim 2 , wherein the control circuit comprises a second control loop configured to control switches of the multi-level switched capacitor modulator such that the output voltage follows the input signal.

8. The voltage modulator of claim 7 , wherein the second control loop comprises:
a second error amplifier configured to:
receive the input signal and the output voltage; and
output an error signal representing a difference between the output voltage and the input signal;

a plurality of comparators, each configured to receive the error signal generated by the second error amplifier and a saw tooth signal associated with the comparator and to generate a pulse width modulation signal;
a switch control signal generator configured to generate switch control signals to the multi-level switched capacitor modulator based on the pulse width modulation signals generated by the plurality of comparators of the second control loop; and
wherein the saw tooth signals associated with the different comparators have different DC levels.

9. The voltage modulator of claim 8 , wherein the switch control signal generator of the second control loop comprises delay stages configured to tune switching instants.

10. The voltage modulator of claim 1 , wherein the switched voltage regulator is a buck or boost converter.

11. The voltage modulator of claim 1 , further comprising a load connected to the output node, wherein an impedance of the load is variable.

12. The voltage modulator of claim 1 , wherein the multi-level switched capacitor modulator is a charge-pump based multi-level switched capacitor modulator.

13. The voltage modulator of claim 1 , wherein the multi-level switched capacitor modulator comprises a multi-level charge pump.

14. An electronic device, comprising:
a voltage modulator; and
wherein the voltage modulator comprises:
a multi-level switched capacitor modulator;
a switched voltage regulator;
an input node to receive an input signal and an output node to output a voltage;
wherein an output of the multi-level switched capacitor modulator and an output of the switched voltage regulator are both connected to the output node of the voltage modulator; and
a control circuit configured to control the switched voltage regulator and the multi-level switched capacitor modulator such that the output voltage follows the input signal.

15. A wireless transceiver, comprising
a voltage modulator; and
wherein the voltage modulator comprises:
a multi-level switched capacitor modulator;
a switched voltage regulator;
an input node to receive an input signal and an output node to output a voltage;
wherein an output of the multi-level switched capacitor modulator and an output of the switched voltage regulator are both connected to the output node of the voltage modulator; and
a control circuit configured to control the switched voltage regulator and the multi-level switched capacitor modulator such that the output voltage follows the input signal.

16. A power amplifier module, comprising:
a voltage modulator; and
wherein the voltage modulator comprises:
a multi-level switched capacitor modulator;
a switched voltage regulator;
an input node to receive an input signal and an output node to output a voltage;
wherein an output of the multi-level switched capacitor modulator and an output of the switched voltage regulator are both connected to the output node of the voltage modulator; and
a control circuit configured to control the switched voltage regulator and the multi-level switched capacitor modulator such that the output voltage follows the input signal.

17. A method of generating an output voltage to follow a input signal, the method comprising:
combining an output of a switched voltage regulator and an output of a multi-level switched capacitor modulator to generate the output voltage;
controlling, by a first control loop, switches of the switched voltage regulator such that a voltage stored in a storage capacitor of the multi-level switched capacitor modulator reaches a value set by a control signal; and
controlling, by a second control loop, switches of the multi-level switched capacitor modulator such that the output voltage follows the input signal.

18. The method of claim 17 , wherein the multi-level switched capacitor modulator is a charge-pump based multi-level switched capacitor modulator.

19. The method of claim 17 , wherein the multi-level switched capacitor modulator comprises a multi-level charge pump.

Assignees

• Ericsson Telefon Ab L M
• ERICSSON TELEFON AB L M (publ)

Inventors

• Ek Staffan

Classifications

• H02M2001/0045

  Electricity · mapped topic

• H04W88/02

  Terminal devices · CPC title

• H03F3/20

  Power amplifiers, e.g. Class B amplifiers, Class C amplifiers (H03F3/26 - H03F3/30 take precedence) · CPC title

• H02M3/07 Primary

  using capacitors charged and discharged alternately by semiconductor devices with control electrode {, e.g. charge pumps} · CPC title

• H03F2200/504

  the supply voltage or current being continuously controlled by a controlling signal, e.g. the controlling signal of a transistor implemented as variable resistor in a supply path for, an IC-block showed amplifier · CPC title