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EP-4742520-A1 - AUTOMATICALLY RECONFIGURABLE CHARGE PUMP SYSTEM

EP4742520A1EP 4742520 A1EP4742520 A1EP 4742520A1EP-4742520-A1

Abstract

Charge pump system (100) comprising: - a charging pump (1) comprising a number of pump stages, each pump stage being configured to be either switched on or switched off, - a voltage regulator (LDO) connected to the charging pump (1) - an activation device configured for: - obtain a prediction result corresponding to a difference between a prediction voltage (Vcp+1) representative of a change in the number of pump stages (Si) activated and a regulator output voltage (Vldo), - modify or not the number of pump stages N (Si) activated according to the prediction result obtained, so as to modify or not the pump output voltage (Vcp) so that the difference between the pump output voltage (Vcp) and the regulator output voltage (VIdo) is regulated and within a predefined operating voltage range.

Inventors

  • BECHET, Gwenael
  • BERAUD-SUDREAU, Quentin

Assignees

  • Commissariat à l'Energie Atomique et aux Energies Alternatives

Dates

Publication Date
20260513
Application Date
20251107

Claims (15)

  1. Charge pump system (100) comprising: - a charge pump (1) connected between an input terminal (IN) and a reference terminal (GND) to an external input power supply to the charge pump system (100) to receive an input supply voltage (Vin) and to generate, depending on the input supply voltage (Vin), at the output of the charge pump (1) between an output terminal (OUT) and the reference terminal (GND), a pump output voltage (Vcp), the charge pump (1) comprising a number Nmax of pump stages (Si), and each pump stage (Si) being configured to be activated or deactivated, the number N of activated pump stages (Si) being between 0 and Nmax, - a voltage regulator (LDO) connected to the charge pump (1) between the output terminal (OUT) and the reference terminal (GND), and configured to receive the pump output voltage (Vcp) at the input of said voltage regulator (LDO) and to generate, based on the pump output voltage (Vcp), a regulator output voltage (Vldo), - an activation device configured for: - obtain a prediction result corresponding to a difference between a prediction voltage (Vcp+1, V CPN-1 ) representative of a change in the number of pump stages (Si) activated and the regulator output voltage (Vldo), - modify or not the number of pump stages N (Si) activated according to the prediction result obtained, so as to modify or not the pump output voltage (Vcp) so that the difference between the pump output voltage (Vcp) and the regulator output voltage (Vldo) is regulated and within a predefined operating voltage range.
  2. Charge pump system (100) according to claim 1, wherein the charge pump is of the step-down type, further comprising a prediction circuit (2) configured to generate said prediction voltage (Vcp+1) at the output of the prediction circuit (2).
  3. Charge pump system (100) according to claim 2, wherein the prediction voltage (Vcp+1) is representative of a change in the number of pump stages (Si) activated corresponding to a number of stages greater than a current activated number of charge pump stages.
  4. A charge pump system (100) according to any one of claims 2 to 3, wherein each pump stage (Si) is configured to receive an intermediate input voltage (Vfi) at its input and to generate at the output of said pump stage, based on the intermediate input voltage (Vfi), an intermediate output voltage (Vsi), The prediction circuit (2) is configured to take a plurality of intermediate input (Vfi) or output (Vsi) voltages, and the prediction circuit (2) comprises: - a multiplexer (MUX) configured to select an intermediate input voltage (Vfi) from among the sampled intermediate input voltages (Vfi), - at least one modification stage (Mi) configured to generate a prediction voltage (Vcp+1) based on the selected intermediate voltage (Vfi), the at least one modification stage (Mi) being configured to have a structure identical to a pump stage ( Si ) of the charge pump (1).
  5. A charge pump system (100) according to any one of claims 2 to 3, wherein each pump stage (Si) is configured to receive an intermediate input voltage (Vfi) at its input and to generate, at the output of said pump stage, based on the intermediate input voltage (Vfi), an intermediate output voltage (Vsi), the prediction circuit (2) comprising: - a resistive voltage divider bridge connected between a first terminal chosen between the output terminal (OUT) and the input terminal (IN) and a second terminal corresponding to the reference terminal (GND), the resistive voltage divider bridge comprising a plurality of resistive components (Ri), each resistive component (Ri) being configured such that the voltage across each resistive component corresponds to the intermediate input voltage (Vfi) or the intermediate output voltage (Vfi) of the corresponding pump stage (Si), - a multiplexer (MUX) connected to the terminals of at least one resistive component of the plurality of resistive components (Ri) and configured to select a voltage from among the voltages across the resistive components, the selected voltage corresponding to the prediction voltage (Vcp+1).
  6. Charge pump system (100) according to claim 5 in which each resistive component (Ri) has between the terminals of said resistive component (Ri) a resistance value defined according to the number of pump stage(s) activated.
  7. Charge pump system (100) according to any one of claims 2 to 6, wherein said charge pump is of the step-down type, and wherein the activation device is configured to: - measure a first voltage difference between the current pump output voltage (Vcp) and the regulator output voltage (Vldo), - if said first difference is less than a low threshold (Tl), modify (E2) the number of pump stages activated by reducing said number of pump stages activated N, - - if said first difference is greater than a high threshold (Th), obtain said prediction result corresponding to a second difference between the prediction voltage (Vcp+1) and the regulator output voltage (Vldo), and if the prediction result is greater than the low threshold (TI), modify the number of activated pump stages by increasing said number of activated pump stages and - maintain unchanged the number of activated pump stages N if the first difference is between the lower threshold (TI) and the upper threshold (Th).
  8. Charge pump system (100) according to claim 1, wherein said charge pump is of the lift type, and wherein the prediction voltage is a lower number of stages voltage (V CPN-1 ) representative of a change in the number of pump stages (Si) activated corresponding to a number of stages less than a current activated number of stages of the charge pump, the prediction result corresponding to a lower number of stages result.
  9. Charge pump system (100) according to claim 8, wherein the activation device is configured to: - measure a first voltage difference between the current pump output voltage (Vcp) and the regulator output voltage (Vldo), - if said first difference is less than a low threshold (TI), modify the number of activated pump stages by increasing said number of activated pump stages N,), - if said first difference is greater than a high threshold (Th) obtain a lower number of stages voltage (V CPN-1 ), and obtain a prediction result for a lower number of stages corresponding to a second difference between a lower number of stages voltage (V CPN-1 ) and the regulator output voltage (Vldo), and, if the prediction result is greater than the low threshold (TI), modify the number of activated pump stages by decreasing said number of activated pump stages, maintain unchanged the number of activated pump stages N if said first difference is between the lower threshold and the upper threshold.
  10. Charge pump system (100) according to any one of the preceding claims, wherein the activation device comprises a set of comparators (A1, A2, A3, A1', A2', A3') comprising: - A first comparator (A1, A1') configured to receive as input the pump output voltage (Vcp), the regulator output voltage (Vldo) as well as the lower threshold (TI) and to compare the difference between the pump output voltage (Vcp) and the regulator output voltage (Vldo) with the lower threshold (TI), - A second comparator (A2, A2') configured to receive as input the pump output voltage (Vcp), the regulator output voltage (Vldo) and the high threshold (Th) and to compare the difference between the pump output voltage (Vcp) and the regulator output voltage (Vldo) with the high threshold (Th), and - A third comparator (A3, A3') configured to receive as input the prediction voltage (Vcp+1, V CPN-1 ), the regulator output voltage (Vldo) as well as the low threshold (TI) and to compare the difference between the prediction voltage (Vcp+1, V CPN-1 ) and the regulator output voltage (Vldo) with the low threshold (TI).
  11. Charge pump system (100) according to any one of the preceding claims wherein each pump stage (Si) of rank i comprises a capacitive component (Cfly) comprising a first electrode connected on one side to an input of the pump stage (Si), and on the other side connected by a first switch (Int1-i) to the input of the pump stage (Si+1) of rank i+1 or the output voltage; and a second electrode connected on one side by a second switch (Int2-i) to the output terminal (VOUT) and on the other side by a third switch Int3-i to the reference terminal (GND).
  12. Charge pump system (100) according to any one of the preceding claims further comprising a microelectromechanical system (Rmems) connected at the output of the voltage regulator (LDO) between the reference terminal (GND) and an output terminal of the regulator (X).
  13. Method for configuring the number of activated pump stages for a charging pump system (100) comprising: - a charge pump (1) connected between an input terminal (IN) and a reference terminal (GND) to an external input power supply to the charge pump system (100) to receive an input supply voltage (Vin) and to generate, depending on the input supply voltage (Vin), at the output of the charge pump (1) between an output terminal (OUT) and the reference terminal (GND), a pump output voltage (Vcp), the charge pump (1) comprising a maximum number Nmax of pump stages (Si), and each pump stage (Si) being configured to to be activated or deactivated, the number of pump stages N (Si) activated being between 0 and Nmax, - a voltage regulator (LDO) connected to the charge pump (1) between the output terminal (OUT) and the reference terminal (GND), and configured to receive the pump output voltage (Vcp) at the input of said voltage regulator (LDO) and to generate, based on the pump output voltage (Vcp), a regulator output voltage (Vldo), The process includes the following steps: - measurement (E1, E1') of a first voltage difference between the pump output voltage (Vcp) and the regulator output voltage (Vldo), - if said first difference is less than a low threshold (TI), operate (E2, E2') a first modification of the number of pump stages activated, - if said first difference is greater than the upper threshold (Th), generate or obtain a prediction voltage (Vcp+1, V CPN-1 ) representative of a change in the number of pump stages (Si) activated, and obtain a prediction result corresponding to a second difference between the prediction voltage (Vcp+1, V CPN-1 ) and the regulator output voltage (Vldo), and, if the prediction result is greater than the lower threshold (TI), make a second change (E4, E4') in the number of pump stages activated, the first and second changes corresponding respectively to an increase or a decrease, or vice versa, - if said difference is between the lower threshold and the upper threshold, maintain unchanged the number of activated pump stages N.
  14. A method according to claim 15, wherein said charging pump is of the step-down type, and wherein: - the first change is a reduction in the number of activated floors, - the second modification is an increase in the number of activated pump stages, - the prediction voltage (Vcp+1) is obtained by a prediction circuit (2).
  15. A method according to claim 15, wherein said charging pump is of the lifting type, and wherein: - the first change is an increase in the number of activated floors, - the second modification is a reduction in the number of activated pump stages, - the prediction voltage corresponds to a voltage of a lower number of stages (V CPN-1 ).

Description

technical field The invention relates to energy conversion in integrated electronic circuits. In particular, the invention relates to a charge pump system comprising, among other things, a charge pump, a voltage regulator, and a prediction circuit. Previous Technique A linear voltage regulator, or "low dropout regulator" in English terminology, is an electronic device that maintains a constant output voltage despite variations in the input voltage. Unlike switching regulators, linear voltage regulators are valued for their simple design, low electrical noise, and rapid response to load changes, making them suitable for sensitive applications. A charge pump is an electronic circuit that converts an input voltage to a higher or lower output voltage using switches and capacitors. Charge pumps are often used to efficiently generate the required voltage in a system without the need for transformers or inductors. A charge pump can be used to power a voltage regulator. The charge pump provides a supply voltage adjusted to the regulator. The charge pump can increase or decrease the input voltage to bring it closer to the output voltage required by the voltage regulator. This allows the voltage regulator to operate more efficiently, as the difference between the input and output voltages is reduced, thus minimizing power losses and improving the overall system efficiency. A linear voltage regulator receives an input voltage and regulates this input voltage to provide a stable output voltage. An internal or external reference to the linear voltage regulator, called the control voltage, determines the value of the output voltage. The linear voltage regulator compares the control voltage to the output voltage via a feedback network and adjusts the output voltage to minimize the error between the control voltage and the feedback voltage. The operating mode of the linear voltage regulator, whether in regulation or linear mode, depends on the relationship between the supply voltage and the output voltage. When the supply voltage is sufficiently higher than the output voltage, The linear voltage regulator operates efficiently in regulation mode. If the supply voltage drops below a given threshold and approaches the output voltage, the linear voltage regulator may enter linear mode, where voltage regulation and noise rejection are degraded, more heat is generated, and the system efficiency decreases. The control voltage of the linear regulator is critical to this dynamic. If the control voltage changes, for example, decreasing due to a temperature change in the surrounding environment, the linear voltage regulator must adjust the output voltage accordingly. If the linear voltage regulator fails to maintain the necessary difference between the supply and output voltages, it may operate in linear mode, thus degrading system performance. It is known in the prior art to keep the linear voltage regulator within its operating range by selecting a static input voltage that is suitable for the highest value of the output voltage to be addressed. However, in this case, the overall efficiency for low output voltages is suboptimal. Furthermore, this solution is not suitable when the input voltage itself varies over time. The aim of the present invention is to overcome the drawback presented above and to allow operation in regulation of the linear voltage regulator which is not influenced by variations in the control voltage or the input voltage. Summary of the invention The present invention relates to a charging pump system comprising: a charge pump connected between an input terminal and a reference terminal to an external input power supply to the charge pump system to receive an input supply voltage and to generate, depending on the input supply voltage, at the output of the charge pump between an output terminal and the reference terminal, a pump output voltage, the charge pump comprising a number Nmax of pump stages, and each pump stage being configured to be activated or deactivated, the number N of activated pump stages being between 0 and Nmax, a voltage regulator connected to the charging pump between the output terminal and the reference terminal, and configured to receive the pump output voltage at the input of said voltage regulator and to generate, based on the pump output voltage, a regulator output voltage, an activation device configured for: to obtain a prediction result corresponding to a difference between a voltage of representative prediction of a change in the number of activated pump stages and the regulator output voltage, modify or not the number of pump stages N activated according to the prediction result obtained, so as to modify or not the pump output voltage so that the difference between the pump output voltage and the regulator output voltage is regulated and within a predefined operating voltage range. Advantageously, powering the voltage regulator with a charge pump improves the efficiency of the c