Voltage regulator

1. A voltage regulator comprising:

a control element;

a current feedback circuit;

a negative voltage feedback circuit; and

a switch for switching between a first mode as a switching regulator and a second mode as a linear regulator and for generating a digital control signal for triggering the control element in the first mode as a switching regulator based on a sum variable, and for generating a linear control signal for triggering the control element in the second mode as a linear regulator based on the sum variable,

wherein, in the first mode as a switching regulator and in the second mode as a linear regulator, a first output of the current feedback circuit and a second output of the negative voltage feedback circuit are coupled to form the sum variable.

2. The voltage regulator according to claim 1 , wherein for coupling, the first output of the current feedback circuit and the second output of the negative voltage feedback circuit are connected to a current summing node.

3. The voltage regulator according to claim 2 , wherein for coupling, a first output current of the current feedback circuit and a second output current of the negative voltage feedback circuit are summed in the current summing node with an opposite sign.

4. The voltage regulator according to claim 1 , wherein a sum variable is a voltage that drops across a resistor, and wherein the resistor is connected to the current summing node.

5. The voltage regulator according to claim 1 , wherein the current feedback circuit is formed to generate an output current, which depends on the current through the control element and is proportional to the current through the control element.

6. The voltage regulator according to claim 1 , further comprising a compensation network, the compensation network being connected to the negative voltage feedback circuit.

7. The voltage regulator according to claim 6 , wherein the compensation network is connected to the current summing node.

8. The voltage regulator according to claim 1 , wherein the switch has an amplifier for amplifying the linear control signal and a driver for outputting the digital control signal.

9. The voltage regulator according to claim 8 , wherein the amplifier is connected to the driver.

10. The voltage regulator according to claim 1 , further comprising a control circuit for triggering the switch to switch between the first mode and the second mode.

11. The voltage regulator according to claim 10 , wherein the control circuit is configured in the second mode as a linear regulator to switch the linear control signal via the driver to an input of the control element.

12. The voltage regulator according to claim 1 , wherein the switch has a circuit for generating the digital control signal based on the sum variable.

13. A method for switching a voltage regulator between a first mode as a switching regulator and a second mode as a linear regulator, the method comprising:

generating a digital control signal for triggering a control element in the first mode based on a sum variable;

switching between the first mode and the second mode; and

generating a linear control signal for triggering the control element in the second mode as a linear regulator based on the sum variable,

wherein, in the first mode as a switching regulator and in the second mode as a linear regulator, a first output of a current feedback circuit and a second output of a negative voltage feedback circuit are coupled to form the sum variable.