Variable input voltage charge pump

A device for providing an output voltage based on a variable input voltage, the device comprising:

• a charge-pump comprising a plurality of cells, wherein each of the plurality of cells can be configured as an input cell, a stepping cell, or a load cell;
• a comparator, the comparator having (i) a first comparator input coupled to receive a reference voltage, (ii) a second comparator input coupled to receive as a comparison voltage either one of the output voltage or a fraction of the output voltage, and (iii) a comparator output, wherein the comparator output changes its state in response to a comparison of the comparison voltage with the reference voltage indicating a transition of the comparison voltage above or below the reference voltage;
• a differentiator coupled to the comparator output, wherein the differentiator is configured to monitor the comparator output and produce a reset pulse each time the comparator output changes its state;
• a decimator for receiving the reset pulse, wherein the decimator resets its count in response to the reset pulse, the decimator having a predetermined decimation count and configured for counting a number of clock periods that occur in response to not being reset by the differentiator, the decimator further providing an output signal in response to each occurrence of counting up to a multiple of the predetermined decimation count;
• an up/down counter having a counter input, an up/down control input, wherein the up/down control input is coupled to the comparator output for controlling the up/down counter to count up or down in response to a state of the comparator output, and wherein the up/down counter provides a counter output as a function of (i) the output signal of the decimator and (ii) the comparator output;
• and
• a controller for, based on the counter output, detecting whether the device is operating in a first predetermined mode or a second predetermined mode, wherein the first predetermined mode corresponds to a mode of operation of the device in which the variable input voltage is either greater than a constant output voltage or is lower than the constant output voltage up to a predetermined voltage value, and wherein the second predetermined mode corresponds to a mode of operation of the device in which the variable input voltage is lower than the constant output voltage by a voltage greater than the predetermined voltage value.

A device for providing an output voltage based on a variable input voltage, the device comprising:

• a charge-pump comprising a plurality of cells, wherein each of the plurality of cells can be configured as an input cell, a stepping cell, or a load cell, wherein the charge-pump comprises a first node for receiving the variable input voltage, a second node for generating an intermediate voltage, and a third node for providing a constant output voltage, and wherein each of the plurality of cells comprises a capacitor having a first terminal and a second terminal, wherein the first terminal is connected to a first switch, wherein the first switch can be used to connect the first terminal to either the variable input voltage or a ground voltage, wherein the second terminal is connected to a plurality of switches, and wherein the plurality of switches can be used to connect the second terminal to one of the variable input voltage, the intermediate voltage, the constant output voltage, and the ground voltage;
• a comparator, the comparator having (i) a first comparator input coupled to receive a reference voltage, (ii) a second comparator input coupled to receive as a comparison voltage either one of the output voltage or a fraction of the output voltage, and (iii) a comparator output, wherein the comparator output changes its state in response to a comparison of the comparison voltage with the reference voltage indicating a transition of the comparison voltage above or below the reference voltage;
• a differentiator coupled to the comparator output, wherein the differentiator is configured to monitor the comparator output and produce a reset pulse each time the comparator output changes its state;
• a decimator for receiving the reset pulse, wherein the decimator resets its count in response to the reset pulse, the decimator having a predetermined decimation count and configured for counting a number of clock periods that occur in response to not being reset by the differentiator, the decimator further providing an output signal in response to each occurrence of counting up to a multiple of the predetermined decimation count;
• an up/down counter having a counter input, an up/down control input, wherein the up/down control input is coupled to the comparator output for controlling the up/down counter to count up or down in response to a state of the comparator output, and wherein the up/down counter provides a counter output as a function of (i) the output signal of the decimator and (ii) the comparator output;
• and
• a controller for, based on the counter output, detecting whether the device is operating in a first predetermined mode or a second predetermined mode, and wherein the controller is further configured to control a state of each of the first switch and the plurality of switches.