Method for controlling a driver circuit, a driver circuit, a system with a driver circuit, and a method for manufacturing an integrated circuit - Patents.com

Abstract

The present invention relates to a method for controlling a driver circuit, the method including operating an amplifier to provide an output signal, e.g., an electronic signal for driving or controlling a load, e.g., a voltage or current, based on a control signal. The method further includes operating a comparator to provide the control signal by comparing an input signal, e.g., an electronic signal having a lower level or lower amplitude than the output signal, with a feedback signal, the feedback signal being based on the output signal. The method further includes providing a first supply voltage to the comparator and a second supply voltage to the amplifier, the second supply voltage being higher than the first supply voltage.

Description

[Technical field]

[0001] FIELD OF THE DISCLOSURE Embodiments of the present disclosure relate to the field of amplifying electronic signals for driving capacitive loads, in particular for driving loads with high voltages. More particularly, embodiments relate to a method for controlling a driver circuit. Further embodiments relate to a driver circuit. Further embodiments relate to a system with a driver circuit. Further embodiments relate to a method for manufacturing an integrated circuit with a driver circuit. Further embodiments relate to an energy-efficient high-voltage driver circuit for capacitive loads. Further embodiments relate to an electronic circuit for time-continuous or time-discrete high-voltage control of a capacitive component, the electronic circuit comprising an integrated voltage processing. [Background technology]

[0002] Driving capacitive loads, such as actuators such as piezoelectric, thermomechanical, electrostatically activated, or microelectromechanical system based actuators, or energy storage devices, can require high voltages, which are typically provided and controlled by driver circuits, such as amplifier circuits.

[0003] In addition, for HiFi applications requiring high output currents, so-called power amplifiers exist. These audio amplifiers are capable of providing output powers in the regime of several tens of watts and are therefore capable of supplying loudspeakers which are characterized by their extremely low resistance (inductance).

[0004] Some electronic circuits for driving capacitive components, for example for driving them continuously in time, are usually based on the principle of audio amplifiers. In particular, amplifier circuits of classes AB, D and H are widely used.

[0005] Generally, an AB amplifier consists of a continuously controlled push-pull stage of an operational amplifier. The entire circuit is usually constructed as a non-inverting amplifier with a resistive divider in a feedback loop. No additional filter stages are required, since time-continuous input signals are provided with the respective amplification factor at the output. However, the power consumption of this amplifier class is problematic, particularly for high output powers, since the output stage of the operational amplifier permanently conducts currents that are not related to the modulation signal.

[0006] Class H amplifiers are an approach that tries to minimize the high power losses of class AB amplifiers by variably adapting the supply voltage of the output stage by using an external power supply, usually equipped with an up-down converter, which requires a suitable coil that cannot be integrated in the circuit due to its size. Besides the space required for the external elements, the high complexity of this setup is also a disadvantage.

[0007] The output stage of a class D amplifier is usually controlled by pulse width modulation (PWM). Thus, the power losses of a class D amplifier are reduced to the current at the switching moment. To generate the PWM signal, the input signal to be amplified can be sampled by a sawtooth voltage in a comparator. Therefore, an energy-consuming low-pass filter with a sufficiently high cutoff frequency is required after the output stage to filter the fundamental oscillations of the input stage from the high-frequency digital signal. Such a filter after the output stage filters a significant part of the spectrum of the output signal that has been previously amplified, thus reducing the efficiency of the generation of the desired output signal. Alternatively, an amplifier that gives a low total harmonic distortion can be used. Summary of the Invention [Problem to be solved by the invention]

[0008] It is an object of the present invention to provide a concept for a driver circuit which achieves an improved compromise between low power dissipation, low space consumption, high voltage output signal, and low circuit complexity. [Means for solving the problem]

[0009] According to the invention, this problem is solved by providing a first supply voltage to a portion of the driver circuit configured to provide a control signal to an amplifier of the driver circuit and a second supply voltage to the amplifier, the second supply voltage being higher than the first supply voltage. Having a first supply voltage and a second supply voltage makes it possible to provide different supply voltages to different portions of the driver circuit. In particular, operating the portion of the driver circuit configured to provide a control signal with a supply voltage lower than the supply voltage provided to the amplifier stage makes it possible to simultaneously achieve low power consumption, a high output voltage, and minimal total harmonic distortion of the output signal. The low power consumption allows space-saving components to be selected for the setup of the driver circuit.

[0010] An embodiment according to the invention provides a method for controlling a driver circuit. The method includes operating an amplifier to provide an output signal, e.g., an electronic signal for driving or controlling a load, e.g., a voltage or a current, based on a control signal. The method further includes operating a comparator to provide a control signal by comparing an input signal, e.g., an electronic signal with a lower level or amplitude than the output signal, to a feedback signal, where the feedback signal is based on the output signal. The method further includes providing a first supply voltage to the comparator and providing a second supply voltage to the amplifier, where the second supply voltage is higher than the first supply voltage.

[0011] The invention is based on the principle for driving different components of a driver circuit with different voltage levels so as to enable a high voltage output signal by providing a high supply voltage to the output stage, i.e. the amplifier, of the driver circuit, while enabling low signal levels and low power consumption in the logic components or logic components configured to provide the control signals or internal signals of the driver circuit. For example, the control signals may be small compared to the output signals so that it is sufficient to provide the comparator with a low supply voltage. Operating the comparator with a low supply voltage (lower than the second supply voltage) reduces the power consumption of the comparator, for example by reducing the switching current. Since the switching of the comparator may occur at very high frequencies, for example at frequencies higher than the frequency of the input or output signal, for example at least 100 times higher than the frequency of the input signal, reducing the switching power in the comparator is a very efficient way to reduce the power consumption of the driver circuit.

[0012] Providing a first supply voltage to the comparator and a second supply voltage to the amplifier makes it possible to have a high voltage at the output stage of the driver circuit, i.e. at the amplifier, to provide a high voltage output signal, and at the same time have a low voltage level at the control stage of the driver circuit, i.e. at the comparator, to reduce power consumption of the driver circuit.

[0013] Minimizing the power consumption of the driver circuit reduces the heat dissipation of the driver circuit so that the driver circuit can be integrated into a smaller form factor. The possibility of integrating the driver circuit into a smaller form factor and the reduced energy consumption of the driver circuit are beneficial for the application of the driver circuit in mobile and / or battery-powered applications. For example, the driver circuit can be applied to control capacitive components for, for example, loudspeakers or ultrasound applications.

[0014] According to an embodiment, the step of providing the first supply voltage is performed by a first voltage source, and the step of providing the second supply voltage is performed by a second voltage source. Thus, the first supply voltage and the second supply voltage can be selected independently of each other. Providing the first supply voltage and the second supply voltage by two different voltage sources improves the flexibility in the design of the driver circuit and opens the possibility of selecting two different types of voltage sources.

[0015] According to an embodiment, the step of providing the first supply voltage is performed by a first charge pump stage and / or the step of providing the second supply voltage is performed by a second charge pump stage. The charge pump is a space-saving component, so that using a charge pump stage to provide the first supply voltage and the second supply voltage facilitates an integrated design of the driver circuit, for example, without a coil or another inductive element to provide the first supply voltage and / or the second supply voltage. For example, the charge pump provides a high second supply voltage, so that the provision of a high output voltage can be achieved without having external components for voltage processing. Using a charge pump to provide the first supply voltage and / or the second supply voltage is therefore a space-saving and power-saving way to provide a supply voltage to the comparator and / or the amplifier, respectively. Furthermore, using a charge pump facilitates a fully integrated design of the driver circuit.

[0016] According to an embodiment, the amplitude of the control signal is lower than that of the output signal. The low amplitude of the control signal may allow high electromagnetic compatibility (EMC) of the driver circuit even when the control signal is a high-frequency signal. Because the output signal may generally have a lower frequency and / or may be continuous, the high voltage of the output signal may still meet high EMC.

[0017] According to an embodiment, the comparator is operated to provide a continuous-time signal. By operating the comparator to provide a continuous-time signal, the comparator may react particularly quickly to changes in the input signal, such that the control signal may be very accurate and may follow the input signal very quickly. Providing a continuous-time control signal may therefore enable fast control of the load by the output signal. Providing a continuous-time signal to the amplifier may enable providing a high-quality output signal without having additional external filter elements or components. Continuous-time operation may provide a low total harmonic distortion of the output signal, i.e., for example, an output signal that directly follows the input signal.

[0018] According to an embodiment, the comparator is operated to provide a discrete-time signal. Operating the comparator to provide a discrete-time signal may imply a low power consumption of the comparator and a high precision of the control signal. By adjusting the frequency of the control signal, the discrete-time operation may provide a low total harmonic distortion of the output signal, and adjusting the frequency of the control signal may be specific or adaptive.

[0019] According to an embodiment, the comparator includes self-clocking of the comparator. Self-clocking of the comparator avoids the need for a separate clock for the control signal. In addition, self-clocking of the comparator may provide low total harmonic distortion of the output signal by optimizing the circuit, for example by adjusting the frequency of the control signal.

[0020] According to an embodiment, the input signal and / or the output signal are continuous in time, and therefore the method can be applied to control a load based on and with a continuous-time signal.

[0021] According to an embodiment, the input signal and / or the output signal are discrete in time. Thus, the method can be applied to control a load based on a discrete-time signal and to control a load with a discrete-time signal.

[0022] According to an embodiment, the step of operating the amplifier comprises a step of operating a push-pull stage, for example similar to a class AB amplifier stage, which avoids the high standby power of the amplifier, so that the efficiency or power efficiency of the amplifier can be improved by using the push-pull stage.

[0023] According to an embodiment, the step of operating the amplifier comprises controlling at least one transistor of a first type and at least one transistor of a second type, the first type transistor and the second type transistor being transistors of complementary types, the first type transistor and the second type transistor being one of FETs, power FETs, and bipolar junction transistors. For example, the complementary type transistors may be p-type and n-type FETs and PNP bipolar junction transistors or n-type FETs and NPN bipolar junction transistors. For example, the complementary type transistors may be transistors with majority charge carriers of complementary types. Controlling at least one transistor of a first type and at least one transistor of a second type complementary to the first type is particularly beneficial for operating a push-pull stage. Such an operation of the amplifier may reduce or eliminate the standby current of the amplifier, so that the power consumption of the amplifier may be particularly small. At the same time, such an operation of the amplifier may enable an output signal of a high range, for example a high voltage range. Operating FETs as first type transistors and / or second type transistors may be beneficial when the output signal of the driver circuit includes low current or low power. Controlling at least one FET may imply providing the control signal as a voltage, so that the power consumption for providing the control signal may be particularly small. Operating bipolar junction transistors as first type transistors and / or second type transistors may be beneficial when the output signal includes high power or high current.

[0024] According to an embodiment, the step of operating the amplifier comprises, during each time instance of the first operating state, for example, controlling at least one transistor of a first type either in a conductive state or in a cut-off state and at least one transistor of a second type in the other state based on a control signal, for example a voltage or a current of the control signal. Controlling the at least one transistor of the first type and the at least one transistor of the second type in complementary states may imply low power consumption of the amplifier.

[0025] According to an embodiment, the method further comprises the step of deriving a feedback signal from the output signal such that the ratio of the amplitude of the feedback signal to the amplitude of the output signal corresponds to the gain of the driver circuit. For example, the step of deriving a feedback signal from the output signal may comprise the step of dividing the voltage of the output signal by the gain. Thus, the gain between the input signal and the output signal may be selected by deriving the feedback signal from the output signal, for example by dividing the output signal accordingly. That is, the step of controlling the driver circuit may comprise the step of adjusting the gain of the driver circuit and providing high flexibility in controlling the driver circuit. Alternatively, the gain of the driver circuit may be fixed to reduce the complexity of the driver circuit.

[0026] According to an embodiment, the first supply voltage is at least 1 / 2, preferably at least 1 / 5, and more preferably at least 1 / 10 of the second supply voltage. For example, the level of the second supply voltage may set an upper limit for the output voltage level. That is, the second supply voltage may be set according to the requirements of the application of the driver circuit. Although the second supply voltage meets the requirements of the application, a high ratio of the second supply voltage to the first supply voltage facilitates the operation of the comparator at low supply voltages. Thus, a high ratio of the second supply voltage to the first supply voltage may imply a particularly low power consumption of the comparator, so that controlling the driver circuit can combine high power efficiency with a high output voltage.

[0027] According to an embodiment, the first supply voltage and / or the second supply voltage are constant. If the first supply voltage and / or the second supply voltage are constant, it may be particularly efficient to provide the first supply voltage and / or the second supply voltage, respectively, by a charge pump.

[0028] According to an embodiment, providing the first supply voltage comprises modulating the first supply voltage and / or providing the second supply voltage comprises modulating the second supply voltage. By modulating the first supply voltage and / or the second supply voltage, the modulated supply voltage can be adapted to the operating state of each time instance of the modulation, for example the power provided by the output signal. By modulating the first supply voltage and / or the second supply voltage, the power consumption of the driver circuit can be particularly low. Modulating the second supply voltage can provide a high efficiency of the push-pull stage. As a non-limiting example, the modulation of the second supply voltage can be realized by suitably controlling two resistors or MOSFETs using either a current or a voltage, which resistors or MOSFETs can be located in the positive and negative supply rail paths, which can connect the second voltage supply stage to the amplifier, for example. As a non-limiting example, the second supply voltage can be controlled according to a control signal for the amplifier, for example for the push-pull stage.

[0029] According to an embodiment, operating the amplifier includes self-adjusting a maximum current conducted through or passing through the push-pull stage, the self-adjustment of the maximum current being based on the load. As a non-limiting example, the self-adjustment of the maximum possible (drive) current through the amplifier, for example through the push-pull stage, may include self-adjusting the maximum current depending on the load at each time instance of the modulation. For example, the self-adjustment of the maximum current may be based on a control signal. Since the control signal is based on a feedback signal based on the output signal, the maximum current may be adjusted based on the power required by the output signal. That is, the maximum current may be self-adjusted during operation of the driver circuit. Thus, the driver circuit may provide high power efficiency and low or optimal THD at the same time and independently of the size of the load. For example, for a small load, operating the driver circuit includes conducting a low maximum current through the amplifier and enabling low power consumption, and for a large load, operating the driver circuit includes conducting a high maximum current through the amplifier and thus providing low THD. As a non-limiting example, self-regulation of the maximum current may be achieved by controlling multiple resistors or multiple MOSFETs using either a current or a voltage. As a non-limiting example, self-regulating the maximum current may be based on a control signal.

[0030] A further embodiment according to the invention provides a driver circuit, e.g. for driving or controlling a load. The driver circuit comprises an amplifier configured to provide an output signal, e.g. an electronic output signal such as a voltage, based on a control signal, e.g. an amplifier, e.g. a control voltage or a control current configured to control a magnitude or amplitude of the output signal. The driver circuit further comprises a comparator configured to provide a control signal by comparing an input signal with a feedback signal, the feedback signal being based on the output signal of the amplifier. For example, the comparator may be part of a feedback loop. The comparator is connected to a first voltage supply stage configured to provide a first supply voltage to the comparator. The amplifier is connected to a second voltage supply stage configured to provide a second supply voltage to the amplifier. The second supply voltage is higher than the first supply voltage.

[0031] The driver circuit relies on the same ideas as the methods described above and provides the same or equivalent functionality and advantages. The driver circuit may optionally be combined with or supplemented by any of the features, functionality, and details described herein with respect to the corresponding methods for controlling the driver circuit. The driver circuit may optionally be combined with the described features, functionality, and details either individually or in any combination thereof.

[0032] According to an embodiment, the driver circuit forms at least part of an integrated circuit. Because the driver circuit is part of the integrated circuit, it can be implemented in a particularly space-saving manner.

[0033] Implementing the driver circuit in an integrated circuit is particularly beneficial in combination with the feature that the first voltage supply stage includes a first charge pump stage and the second voltage supply stage includes a second charge pump stage. The charge pump stage may be integrated in an integrated circuit and still provide a high voltage. Thus, if the driver circuit includes a first charge pump stage configured to provide a first supply voltage to the comparator and further includes a second charge pump stage configured to provide a second supply voltage to the amplifier, the driver circuit may be implemented in an integrated circuit including a first voltage supply stage and a second voltage supply stage. Such a configuration avoids the need for external, e.g., discrete components such as conductance or resistance or capacitance.

[0034] Implementing the driver circuit in an integrated circuit may be further beneficial in combination with the feature that the amplifier comprises at least one FET of n-type and at least one FET of p-type, for example at least one n-type MOSFET and at least one p-type MOSFET. Such a structure of the driver circuit allows the driver circuit to be manufactured by a CMOS process. Further combining these two features with the feature that the first voltage supply stage comprises a first charge pump and the second voltage supply stage comprises a second charge pump allows the driver circuit to be manufactured in a CMOS process, including the first voltage supply stage and the second voltage supply stage. Manufacturing the driver circuit with a CMOS process may be a very cost-effective and flexible way to produce the driver circuit, allowing the driver circuit to be integrated into an integrated circuit with further components.

[0035] A further embodiment according to the invention provides a system comprising a load and a driver circuit. The system is configured to control the load based on an output signal of the driver circuit. By controlling the load using the driver circuit, the load can be controlled by an input signal that may be smaller than the output signal, for example, such that the load can be controlled by using a small signal. For example, the driver circuit can be adapted to the load, i.e., for example, the level of the output signal can be adapted to the load and / or the power provided by the driver circuit can be adapted to the requirements of the load.

[0036] According to an embodiment, the system comprises an integrated circuit, the integrated circuit comprising the driver circuit. Because the integrated circuit comprises the driver circuit, the system may be particularly space-saving and / or energy-efficient and may be produced very cost-effectively by using manufacturing processes for integrated circuits.

[0037] According to an embodiment, the load comprises a capacitance and / or an inductance, and the resistance of the load is higher than 10 kΩ or 100 kΩ or 1 MΩ. Because the resistance of the load is so high, the current required to be provided by the driver circuit to drive the load may be low, even if the voltage of the output signal of the driver circuit used to drive the load may be high. Thus, by adapting the design of the driver circuit to the power consumption of the load, the driver circuit can drive the load with little power consumption. Since the driver circuit comprises a first and a second voltage supply stage, it can be adapted to the load very efficiently by adapting the voltage supply stages individually.

[0038] For example, the maximum output power of the driver circuit, e.g. the output power of the driver circuit provided by the output signal, can be designed to be low, e.g. in the mW regime. The second voltage supply stage may thus include a charge pump stage for providing a second supply voltage and still be able to provide a sufficiently high power to the amplifier. With further adaptation of the driver circuit to low output power, the output signal can be configured to have a low level or low amplitude. With a low level of the control signal, the power consumption of the comparator can be low so that the comparator can be sufficiently supplied by the charge pump stage. Thus, combining the driver circuit with a load with a high resistance allows an integrated design of the system, and the driver circuit including the first voltage supply stage and the second voltage supply stage can be part of an integrated circuit, e.g. an integrated circuit manufactured by a CMOS process. Thus, the configuration of the system can be particularly space-saving and / or the system can be configured to be particularly power-efficient.

[0039] According to an embodiment, the load comprises a MEMS actuator. The MEMS actuator may be integrated into an integrated circuit, such that a system comprising the MEMS actuator and driver circuitry may be integrated into a common integrated circuit. The system may therefore be particularly space-efficient and may be manufactured in a co-manufacturing process for the integrated circuit.

[0040] According to an embodiment, the load comprises a piezoelectric or thermomechanical actuator or an energy storage device. These components may comprise highly capacitive loads or may comprise capacitance and / or inductance and / or may comprise high resistance so that they can be advantageously driven by a driver circuit, which may for example comprise a charge pump stage for providing a second supply voltage of the driver circuit.

[0041] According to an embodiment, the load comprises at least one of a loudspeaker, a microphone, a pump, a valve, a health assistance system, a positioning system, and a mechanical control for moving the plate. These components may comprise highly capacitive loads, i.e., they may comprise high capacitance and / or high resistance, such that they may be advantageously driven by the driver circuit, even if the driver circuit comprises a charge pump stage for providing the second supply voltage.

[0042] A further embodiment according to the invention provides a method for manufacturing an integrated circuit, comprising the step of configuring an amplifier such that the amplifier is configured to provide an output signal based on a control signal. The method further comprises the step of configuring a comparator such that the comparator is configured to provide the control signal by comparing an input signal with a feedback signal, the feedback signal being based on the output signal of the amplifier. Additionally, the method includes the step of configuring the first voltage supply stage to provide a first supply voltage to the comparator, and the second voltage supply stage to provide a second supply voltage to the amplifier, the second supply voltage being higher than the first supply voltage, and configuring the first voltage supply stage and the second voltage supply stage.

[0043] A further embodiment according to the invention provides a computer program configured to implement the above mentioned methods for controlling a driver circuit when the computer program is executed on a computer or a signal processor such that one of the computer programs implements the above mentioned methods.

[0044] Hereinafter, embodiments of the present disclosure will be described in more detail with reference to the drawings. [Brief description of the drawings]

[0045] [Figure 1] 1 is a schematic representation of a driver circuit according to one embodiment. [Diagram 2] 13 is a schematic representation of a driver circuit according to a further embodiment; [Diagram 3] 1 is a schematic representation of a system with a driver circuit according to one embodiment. [Figure 4A] 2 is a diagram of input, output, feedback and control signal changes over time according to one embodiment; [Figure 4B] 2 is a diagram of input, output, feedback and control signal changes over time according to one embodiment; [Diagram 5] FIG. 2 is a block diagram of a method for controlling a driver circuit, according to one embodiment. [Figure 6] 1 is a block diagram of a method for manufacturing an integrated circuit, according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0046] Equal or equivalent elements or elements with equal or equivalent functionality are designated in the following description with equal or equivalent reference numbers, even if they occur in different drawings.

[0047] Method steps illustrated by block diagrams and described by reference to said blocks may be performed in an order different from that shown and / or described. Furthermore, method steps relating to a particular feature of a device may be interchangeable with said feature of said device, and vice versa.

[0048] In the following description, a number of details are set forth to provide a more thorough description of the embodiments of the present invention. However, it will be apparent to those skilled in the art that the embodiments of the present invention may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form rather than in detail to avoid obscuring the embodiments of the present invention. In addition, unless otherwise specified, the features of different embodiments described below may be combined with each other.

[0049] Throughout the description, all features, functionality, and details described as examples should be understood to be optional and non-exclusive.

[0050] 1 shows a schematic representation of a driver circuit 100 according to an embodiment. The driver circuit 100 comprises an amplifier 180 configured to provide an output signal 182 based on a control signal 122. The driver circuit 100 further comprises a comparator 120 for providing the control signal 122 by comparing an input signal 110 with a feedback signal 162, the feedback signal 162 being based on the output signal 182 of the amplifier 180. The comparator 120 is connected to a first voltage supply stage 140 configured to provide a first supply voltage 142 to the comparator 120. The amplifier 180 is connected to a second voltage supply stage 150 configured to provide a second supply voltage 152 to the amplifier 180, the second supply voltage 152 being higher than the first supply voltage 142.

[0051] According to the operating principle of the driver circuit 100, by receiving a feedback signal 162 based on the output signal 182, the comparator is able to provide a control signal 122 to the amplifier 180 so that the amplifier 180 can control the output signal 182 according to the input signal 110.

[0052] Because the voltage domain of the control signal 122 is independent of the voltage domain of the output signal 182, the comparator 120 configured to provide the control signal 122 may be provided with a first supply voltage 142 that may be independent of the second supply voltage 152 provided to the amplifier 180 configured to provide the output signal 182.

[0053] The driver circuit 100 according to Fig. 1 may optionally be complemented by all the features, functionalities and details described herein with respect to other driver circuits, each of which may be optionally added to the driver circuit 100, either individually or in any combination thereof.

[0054] 2 shows a schematic representation of a driver circuit 200 according to one embodiment. The driver circuit 200 may be based on the driver circuit 100, for example.

[0055] The driver circuit 200 is configured to provide an output signal 182 based on the input signal 110. For example, the driver circuit 200 may be configured to control an optional load 290 based on the input signal 110 by driving the load 290 with the output signal 182. For example, the driver circuit 200 is configured to provide the output signal 182 to the load 290, where an amplitude of the output signal 182 is adapted to drive the load 290.

[0056] For example, the output signal 182 may be represented by a variable voltage. The voltage of the output signal 182 may cause a current, which may be based on the load 290, e.g., an electrical resistance or impedance of the load 290. In other words, the driver circuit may be configured to provide power to the load 290 by providing the output signal 182 to the load.

[0057] For example, the voltage of the output signal may be in the range of ±24 V. Alternatively, the voltage of the output signal 182 may be less than or greater than ±24 V, e.g., the driver circuit may provide an output voltage in the range of ±400 V. The power provided by the output signal 182 may be, for example, in the mW regime. Alternatively, the power provided by the output signal 182 may be less than or greater than the power in the mW regime.

[0058] The driver circuit 200 is configured to receive an input signal 110. For example, the input signal 110 may be represented by a variable voltage and a current versus that voltage.

[0059] For example, the voltage of the input signal 110 may be within the range of a low voltage or low level signal, such as within ±1 V. Alternatively, the voltage of the input signal 110 may be less than or greater than ±1 V.

[0060] For example, the amplitude of the output signal 182 may be greater than or equal to the amplitude of the input signal 110. In other words, the driver circuit may be configured to amplify the input signal 110 to provide the output signal 182, with the amplification factor of the driver circuit 200 corresponding to the ratio of the amplitude of the output signal 182 to the amplitude of the input voltage 110.

[0061] For example, the input signal 110 and / or the output signal 182 are continuous in time. For example, the input signal 110 and the output signal 182 may be analog signals. Alternatively, the input signal 110 and / or the output signal 182 are discrete in time.

[0062] By amplifying the input signal 110 to provide an output signal 182, the driver circuit 200 comprises a feedback loop 260 comprising a comparator 120, an amplifier 180, and a voltage divider 261, where the comparator 120 is configured to control the amplifier 180 based on a feedback signal 162 provided by the voltage divider 261 based on the output signal 182 provided by the amplifier.

[0063] The voltage divider 261 is configured to provide the feedback signal 162 based on the output signal 182 such that the ratio between the output signal 182 and the feedback signal 162 corresponds to the gain of the driver circuit 200 within an error range that may result from the limited precision and limited speed of the components of the driver circuit. For example, the ratio between the output signal 182 and the feedback signal 162 may be within ±1%, or ±0.1%, or ±0.01% of the gain.

[0064] For example, the voltage divider 261 may comprise one or more resistors, one or more transistors and / or one or more capacitors. The voltage divider 261 may be configured to divide the output signal 182 by an amplification factor to obtain the feedback signal 162. The amplification factor of the driver circuit may be fixed. Alternatively, the voltage divider 261 may be tunable, for example by a tuning bit, such that the ratio between the output signal 182 and the feedback signal 162 may be adjusted, for example, according to the application of the driver circuit 200, for example, according to the load 290 and / or according to the amplitude of the input signal 110.

[0065] That is, the driver circuit 200 comprises a feedback loop 160 configured to derive the feedback signal 162 from the output signal 182 , the ratio between the amplitude of the feedback signal 162 and the amplitude of the output signal 182 corresponding to the amplification factor of the driver circuit 200 .

[0066] The comparator 120 is configured to compare the input signal 110 with the feedback signal 162 to obtain the control signal 122. For example, the comparator 120 may provide the control signal 122 as a digital signal with a high level and a low level, where the comparator is configured to provide the control signal 122 at either a high level or a low level at time instances when the feedback signal 162 is greater than the input signal 110, and at the other level at time instances when the feedback signal 162 is less than the input signal 110.

[0067] For example, the comparator is a continuous-time comparator. For example, the comparator 120 may be configured to provide the control signal 122 as a continuous-time signal.

[0068] Alternatively, the comparator is a discrete-time comparator. For example, the comparator may be configured to provide the control signal 122 as a discrete-time signal.

[0069] For example, the comparator is a discrete-time comparator, and the comparator is self-clocked. For example, the comparator 120 may be configured to provide the control signal 122 as a discrete-time signal, where the control signal 122 includes synchronization information regarding the clock of the control signal 122.

[0070] The amplifier 180 is configured to receive the control signal 122 and control the output signal 182 based on the control signal 122. The amplifier 180 may include a push-pull stage. The push-pull stage may include at least two complementary stages.

[0071] One stage of the at least two complementary stages may comprise a transistor, e.g., a field effect transistor (FET), such as a MOSFET or power FET, or a bipolar junction transistor. The at least two complementary stages of the push-pull stage may comprise a first type of transistor and a second type of transistor complementary to the first type of transistor. For example, the complementary type of transistor may comprise majority charge carriers of the opposite type. For example, the complementary type of transistor may be represented by a p-type FET and an n-type FET, or an npn bipolar junction transistor and a pnp bipolar junction transistor, or a p-type FET and a pnp bipolar junction transistor, or an n-type FET and an npn bipolar junction transistor.

[0072] That is, the amplifier 182 comprises at least one transistor of a first type and at least one transistor of a second type, the first type transistor and the second type transistor being complementary types of transistors, and the first type transistor and the second type transistor being one of a FET, a power FET, or a bipolar junction transistor.

[0073] A stage of the at least two complementary stages may be configured to provide a contribution to the output signal 182 depending on the conductance of the stage. For example, a stage of the at least two complementary stages may be in a conductive state or a cut-off state, which is a state with a low or vanishing conductance compared to the conductance of the conductive state. The amplifier 180 may be configured to provide a signal to the at least two complementary stages based on the control signal 122, which controls the conductance of the at least two complementary stages to be either in a conductive state or in a cut-off state. For example, the amplifier 180 may be configured to control a first stage of the at least two complementary stages to be in a conductive state when the level of the control signal 122 is within a first range, and to control a second stage of the at least two complementary stages to be in a conductive state when the level of the control signal 122 is within a second range. For example, the first and second ranges may be opposite such that for an instantaneous level, e.g., high or low, of the control signal 122, either the first stage or the second stage may be in a conducting state and the other stage may be in a cutoff state. For example, the first and second ranges may overlap such that, at an instant of operation, for values ​​of the control signal 122 that are between a high level and a low level, both stages may be in a conducting state. Such an overlap may be beneficial to avoid artifacts in the output signal.

[0074] For example, the comparator 120 is configured to provide the control signal 122, which has a fast slew rate, for example, greater than 50 MV / s, or greater than 100 MV / s, or greater than 400 MV / s. In addition, the overlap of the first and second ranges of control signal levels may be small, for example, less than 10%, or less than 5%, or less than 1% of the amplitude of the control signal 122. This combination may enable highly efficient operation of the amplifier with particularly low power losses.

[0075] That is, the first type transistor and the second type transistor are configured to change into a conductive state or into a cutoff state, or between a conductive state and a cutoff state, or to change their conductivity based on the control signal 122.

[0076] In other words, the driver circuit 200 is configured to control at least one transistor of a first type to either a conductive state or a cut-off state and at least one transistor of a second type to the other state during each time instance of the first operating state. The driver circuit 200 includes a second voltage supply stage configured to provide a first supply voltage 142 to the comparator 120. The level or amplitude of the first supply voltage 142 may correspond to, for example, a maximum level or amplitude of the control signal 122. The first voltage supply stage may comprise a first voltage slew for providing the first supply voltage 142.

[0077] That is, the amplitude of the control signal may be lower than the amplitude of the output signal.

[0078] For example, the push-pull stage may be realized as an AB amplifier. For example, the push-pull stage may comprise a standard inverter, for example with p-type and n-type FETs. Alternatively, the push-pull stage may comprise a cascaded inverter with delayed or non-overlapping control to avoid short circuit currents at the switching instants. The cascaded inverter may comprise, for example, one or more p-type FETs and one or more n-type FETs in series. Alternatively, the push-pull stage may comprise one or more MOSFETs and / or one or more bipolar junction transistors.

[0079] According to an embodiment, the amplifier 180 is configured to self-adjust the maximum current conducted through or passing through the push-pull stage, the self-adjustment of the maximum current being based on the load 290 .

[0080] For example, the maximum current may be a maximum possible current or an upper limit of a current, e.g., a current used or consumed to provide the output signal 182. For example, the amplifier 180 may be configured to self-adjust the maximum current according to the control signal 122, and thus, e.g., without external influence. For example, the power required to provide the output signal may depend on the load 290, and the amplifier 180 may be configured to obtain information regarding the power required to provide the output signal 182 by using the control signal 122. Thus, the amplifier 180 may be configured to self-adjust the maximum current according to the power consumption or power requirements of the load 290.

[0081] The driver circuit 200 comprises a charge pump 145. The charge pump 145 comprises a first voltage supply stage 140 and a second voltage supply stage 150. According to an embodiment, the first voltage supply stage 140 includes a first charge pump stage configured to provide a first supply voltage 142 to the comparator 120, and the second voltage supply stage 150 includes a second charge pump stage configured to provide a second supply voltage 152 to the amplifier 180. For example, the charge pump 145, the first charge pump stage, and / or the second charge pump stage may comprise a Dickson charge pump.

[0082] That is, the first voltage supply stage 140 includes a first charge pump stage and / or the second voltage supply stage 150 includes a second charge pump stage.

[0083] According to an alternative embodiment, the first charge pump stage may be part of a first charge pump and the second charge pump stage may be part of a second charge pump.

[0084] According to a further alternative embodiment, the driver circuit 200 does not necessarily comprise the charge pump 145. According to this alternative embodiment, the first voltage supply stage 140 may comprise a first voltage source and / or the second voltage supply stage 150 may comprise a second voltage source. For example, the first voltage source and / or the second voltage source may comprise a boost converter, a buck converter, a buck-boost converter, a charge pump, a charge pump stage, or a low-dropout regulator (LDO). As a non-limiting example, the first voltage supply stage 140 and / or the second voltage supply stage 150 may be realized by separate sources and subsequent controllers.

[0085] Thus, the first voltage supply stage 140 may comprise a first voltage source and the second voltage supply stage 150 may comprise a second voltage source.

[0086] The first supply voltage 142 may be adapted to the amplitude of the control signal 122, which may be applied to the amplifier 180 and / or to the amplitude of the output signal 182. For example, the first voltage supply stage 140 may be configured to provide the first supply voltage 142 as a constant or fixed voltage. That is, the first supply voltage 142 may be constant.

[0087] Alternatively, the second voltage supply stage may be configured to modulate the first supply voltage.

[0088] For example, the first supply voltage 142 may be modulated according to, for example, the power consumption of the comparator 120 or the current amplitude of the control signal during each time instance of operation.

[0089] The second supply voltage 152 may be adapted to a maximum level or maximum amplitude of the output signal 182. For example, the second supply voltage 152 may be equal to or greater than the amplitude of the output signal 182.

[0090] According to an embodiment, the second supply voltage 152 may be constant.

[0091] For example, the second voltage supply stage 150 may be configured to provide the second supply voltage 152 as a constant or fixed voltage, which may correspond to a required maximum amplitude of the output signal, for example, as required by the load 290.

[0092] Alternatively, the second voltage supply stage 150 may be configured to modulate the second supply voltage 152 .

[0093] For example, the second supply voltage 152 may be modulated, for example, according to the power consumption of the amplifier 180, for example, a push-pull stage, or according to the required current level of the output signal 182 during each time instance of operation. For example, the second voltage supply stage 150 may comprise a low voltage rail and a high voltage rail, and modulating the second supply voltage 152 may include controlling the respective contributions of the voltage of the low voltage rail and the voltage of the high voltage rail based on the control signal 122. Since the control signal 122 is based on the feedback signal 162, the control signal may include information regarding the required power of the amplifier 180 and / or the output signal 182. Thus, modulating the second supply voltage 152 using the control signal 122 may realize the adjustment of the second supply voltage 152 according to the power consumption of the push-pull stage 280. That is, the driver circuit 200 may be configured to self-adjust the second supply voltage 152. As a non-limiting example, controlling the second supply voltage 152 based on the control signal 122 may be realized by two resistors or MOSFETs.

[0094] The second supply voltage 152 may be adapted to the output signal 182, and the first supply voltage 142 may be adapted to the control signal 122. The first supply voltage 142 may be different from the second supply voltage 152. In particular, the first supply voltage 142 may be smaller than the second supply voltage 152.

[0095] For example, the first supply voltage 142 is at least ½, preferably at least ⅕, and more preferably at least 1 / 10 of the second supply voltage 152 .

[0096] For example, the amplitude of the output signal may be dictated by the application of the driver circuit 200, such as by the load 290. Furthermore, the amplitude of the control signal 122 may be smaller than the amplitude of the output signal 182. The smaller the amplitude of the control signal 122, the more power may be saved during operation of the driver circuit 200.

[0097] According to an embodiment, the driver circuit 200 forms at least part of an integrated circuit.

[0098] For example, the driver circuit 200 may be optionally integrated into an integrated circuit, for example together with the load 290 and / or together with additional components. In particular, the driver circuit 200 may be integrated into an integrated circuit including a first charge pump stage and a second charge pump stage.

[0099] In other words, the driver circuit 200 may be configured to receive a continuous-time input signal 110 with a variable small amplitude. The driver circuit may further be configured to amplify the input signal 110 according to an adjustable resistive divider 261 to obtain a continuous-time output signal 110 with a variable or equal or greater amplitude compared to the small amplitude of the input signal 110. For example, a typical load of the MEMS components forming the main load 290 of the driver circuit may be represented by a capacitor. The continuous-time output signal 182 may be generated by a push-pull inverter stage, for example, the amplifier 180, connected to a high voltage domain, for example, the second supply voltage 152. Furthermore, the push-pull inverter stage may be configured to be controlled by a comparator 120, which may be connected to a low voltage domain, for example, the first supply voltage 142. The low voltage domain and the high voltage domain may be generated by an integrated charge pump 145 and may be fixed at a constant level. The optional initial voltage source for the charge pump 145 may be of any type.

[0100] For example, the operation principle of the driver circuit 200 corresponds to that of a feedback loop. The driver circuit 200 may be configured to return the continuous-time output signal 182 to the input of the comparator 120 via an adjustable voltage divider 261. The comparator 120 may be configured to receive the input signal 110 to a second input and to compare the input signal 110 with the returned feedback signal 162. The comparator 120 may be configured to generate a high or low level signal depending on its input signals, i.e., the input signal 110 and the feedback signal 162, and the comparator 120 may be configured to generate a high or low level signal according to the low voltage region. The comparator 120 may be configured to provide a high or low level signal at the output of the generator 120 as the control signal 122. The driver circuit 200 may be configured to control the amplifier 180, for example, a push-pull inverter stage, based on the resulting control signal 122, such as the completion of the feedback loop. Further, the driver circuit 200 may be configured to rely on MEMS components, such as the capacitance of the load 290, for smoothing or filtering the output signal 182, such that the driver circuit 200 may require fewer external components or filter stages or may not require any additional external components or filter stages.

[0101] In contrast to a conventional class AB amplifier, which may be optimized for resistive loads, the driver circuit 200 comprises a second voltage supply stage 150 configured to provide a second supply voltage 152, i.e., a voltage range of the output signal 182, which is an internal, integrated part of the driver circuit 200. While further conventional solutions rely on boost converters, external components, additional pulse generators, analog-to-digital converters, and further signal processing units to control the output stage, the driver circuit 200 may be implemented fully integrated, comprising a charge pump 145, a comparator 120, e.g., an analog or digital comparator. While further conventional solutions require an RC low-pass output filter, the driver circuit 200 may provide an output signal directly to the load 290. Instead of a bipolar high-voltage power amplifier, the driver circuit 200 may comprise MOSFETs and still provide a high output voltage. Furthermore, the driver circuit 200 may operate with a single stage for voltage and power amplification. The driver circuit 200 comprises two voltage domains, for example, a low voltage domain provided by the first supply voltage 142 and a high voltage domain provided by the second supply voltage 152. In addition, the driver circuit 200 can be configured to drive a variable load, for example, a variable capacitance. Other than conventional amplifiers of class A, B, C, D, AB, G, or H, the driver circuit 200 can efficiently amplify low voltage input signals and efficiently control capacitive loads with high continuous time voltages. Other than some conventional solutions, the driver circuit 200 can be realized, for example, without H-bridges, digital-to-analog converters, separate collector units, and separate pulse width modules.

[0102] In summary, the driver circuit 200 may provide a low complexity circuit design capable of combining a high output voltage with low power consumption. In addition, the driver circuit 200 may optionally utilize components that may be fully integrated into an integrated circuit and fabricated using a CMOS process.

[0103] 3 shows a schematic representation of a system 301 according to one embodiment. The system 301 comprises a driver circuit 300. The driver circuit 300 may correspond to the driver circuits 100, 200. The system 301 further comprises a load 390, which may correspond to the load 290. The system 301 is configured to control the load 390 based on the output signal 182 of the driver circuit 300.

[0104] According to an embodiment, the load 390 includes a capacitance and / or an inductance, and the resistance of the load is higher than 10 kOhm or 100 kOhm or 1 MOhm.

[0105] The load 390 may be characterized by, for example, a capacitance. For example, the load 390 may be purely or mainly capacitive. Alternatively, the load 390 may be mainly capacitive and may further comprise or be characterized by a resistance and / or an inductance, such that the resulting resistance of the load 390 may be in the MOhm regime or may be greater than 10 kOhm, or 100 kOhm, or 1 MOhm. The higher the resistance of the load 390, the lower the power consumption of the amplifier of the driver circuit 300 for a given amplitude of the output signal 182 may be, such that the second supply voltage of the driver circuit 300 may be provided by a charge pump.

[0106] According to an embodiment, the system 301 comprises an integrated circuit, the integrated circuit comprising a driver circuit 300 .

[0107] For example, the driver circuit 300 is part of an integrated circuit. For example, the driver circuit 300 and the load may be part of a joint integrated circuit.

[0108] According to an embodiment, the load 390 comprises a MEMS actuator, or a piezoelectric actuator, or a thermo-mechanical actuator.

[0109] The load 390 comprises, for example, a MEMS component and / or a piezoelectric actuator, for example a bending actuator, for example an electrostatic bending actuator (NED-actuator), a piezoelectric actuator, or a thermo-mechanical actuator.

[0110] According to an embodiment, the load 390 comprises at least one of a loudspeaker, a microphone, a pump, a valve, a health assistance system, a positioning system, and a mechanical control for moving a plate.

[0111] According to a further embodiment, the load 390 comprises an energy storage device.

[0112] The output signal 182 of the driver circuit 300 may be adapted to the characteristics of the load 390. For example, the load 390 may be mainly capacitive such that the driver circuit 300 may be configured to provide low power to the load 390 via the output signal 182. The driver circuit 300 may therefore include a second charge pump stage configured to provide a second supply voltage to the amplifier. The amplifier may comprise a first type and a second type of FET or MOSFET such that the amplifier may be configured to provide the output signal 182 based on a low power control signal, i.e. the current and / or voltage of the control signal may be small. The driver circuit 300 may therefore include a first charge pump stage configured to provide a first supply voltage to a comparator configured to provide the control signal. The first charge pump stage, the second charge pump stage, the comparator, and the amplifier may be integrated in an integrated circuit such that the driver circuit 300 may be fully integrated. The driver circuit 300, optionally, and the load 390 may therefore be manufactured using a CMOS process.

[0113] In contrast, conventional driver circuits, such as classical class AB amplifiers, have one supply voltage range that corresponds to the level of the desired output voltage. For example, power amplifiers are the main application of AB amplifiers. The dominant power consumption of a power amplifier occurs in the output stage, so that the power supply of the power amplifier is configured to provide a large power. Therefore, the power amplifier may rely on external components such as external inductors or capacitors.

[0114] 4A shows a diagram of the input signal 110, the output signal 182, the feedback signal 162, and the control signal 122 over time, according to one embodiment. The diagram shows an example time period of 100 μs.

[0115] FIG. 4B shows a zoomed-in view of the time period 402 of the diagram shown in FIG. 4A.

[0116] 4A and 4B, the feedback signal is derived from the output signal by dividing the output signal by 10, which may be implemented by voltage divider 261. The control signal is generated by comparing the input signal to the feedback signal, such that the level of the control signal corresponds to a low level at times when the feedback signal is greater than the input signal (e.g., time 403 in FIG. 4B) and such that the level of the control signal corresponds to a high level at times when the feedback signal is greater than the input signal (e.g., time 404 in FIG. 4B).

[0117] For example, the amplifier 180 may be configured to adapt the output signal based on the control signal, such that when the level of the control signal provided to the amplifier corresponds to a high level, the amplifier 180 increases the output voltage, and when the level of the control signal provided to the amplifier corresponds to a low level, the amplifier 180 decreases the output voltage. For example, the increase or decrease of the output signal may be performed by switching two complementary stages of the push-pull stage of the amplifier or by changing the weight between the contributions of the two complementary stages of the push-pull stage of the amplifier.

[0118] 5 shows a block diagram of a method 5000 for controlling a driver circuit, e.g., driver circuits 100, 200, 300, according to an embodiment. The method 5000 includes a step 5100 of operating an amplifier 180 to provide an output signal 182 based on a control signal 122. The method 5000 further includes a step 5200 of operating a comparator 120 to provide the control signal 122 by comparing an input signal 110 with a feedback signal 162, the feedback signal 162 being based on the output signal 182. In addition, the method 5000 includes a step 5400 of providing a first supply voltage 142 to the comparator 120 and a step 5500 of providing a second supply voltage 152 to the amplifier 180, the second supply voltage 152 being higher than the first supply voltage 142.

[0119] 5 is chosen exemplarily, i.e., the steps may be performed in any order or in parallel. If the steps of the method 5000 are performed in parallel, the control of the driver circuit may be performed particularly efficiently or quickly.

[0120] 6 shows a block diagram of a method 6000 for manufacturing an integrated circuit according to one embodiment. The method 6000 includes a step 6800 of configuring the amplifier 180 such that the amplifier 180 is configured to provide an output signal 182 based on a control signal 122. The method 6000 further includes a step 6200 of configuring the comparator 120 such that the comparator 120 is configured to provide the control signal 120 by comparing the input signal 110 with a feedback signal 162, the feedback signal 162 being based on the output signal 182 of the amplifier 180. In addition, the method 6000 includes a step 6450 of configuring the first voltage supply stage 140 and the second voltage supply stage 150 such that the first voltage supply stage 140 is configured to provide a first supply voltage 142 to the comparator 120, and the second voltage supply stage 150 is configured to provide a second supply voltage 152 to the amplifier 180, the second supply voltage 152 being higher than the first supply voltage 142.

[0121] The order of steps of method 6000 shown in FIG. 6 is chosen as an example, i.e., the steps may be performed in any order or in parallel.

[0122] Although some aspects have been described in the context of an apparatus, it will be apparent that these aspects also represent descriptions of corresponding methods, and that blocks or devices correspond to method steps or features of method steps. Similarly, aspects described in the context of a method step also represent descriptions of corresponding blocks or items or features of a corresponding apparatus.

[0123] The above-described embodiments merely illustrate the principles of the present invention. It is understood that modifications and variations of the configurations and details described herein will be apparent to those skilled in the art. It is therefore intended to be limited only by the scope of the following patent claims, and not by the specific details presented by the description and illustration of the embodiments herein.

[0124] Some or all of the method steps may be performed by (or using) a hardware apparatus, such as, for example, a microprocessor, a programmable computer, or an electronic circuit. In some embodiments, one or more of the most important method steps may be performed by such an apparatus.

[0125] Depending on some implementation requirements, embodiments of the present invention may be implemented in hardware or software, or at least partially in hardware or at least partially in software. The implementation may be performed using a digital storage medium, such as a floppy disk, DVD, Blu-Ray, CD, ROM, PROM, EPROM, EEPROM, or FLASH memory, having stored thereon electronically readable control signals that cooperate (or are capable of cooperating) with a programmable computer system such that the respective methods are performed. Thus, the digital storage medium may be computer readable.

[0126] Some embodiments according to the invention comprise a data carrier having electronically readable control signals capable of cooperating with a programmable computer system so as to perform one of the methods described herein.

[0127] Generally, embodiments of the present invention may be implemented as a computer program product comprising program code operable to perform one of these methods when the computer program product runs on a computer. The program code may, for example, be stored on a machine-readable carrier.

[0128] Other embodiments comprise the computer program for performing one of the methods described herein, stored on a machine readable carrier.

[0129] In other words, an embodiment of the inventive method is, therefore, a computer program having a program code for performing one of the methods described herein, when the computer program runs on a computer.

[0130] A further embodiment of the inventive method is therefore a data carrier (or digital storage medium, or computer readable medium) with a computer program recorded thereon for performing one of the methods described herein. The data carrier, digital storage medium, or recorded medium may in general be tangible and / or non-transitory.

[0131] A further embodiment of the inventive method is therefore a data stream or a sequence of signals representing the computer program for performing one of the methods described herein. The data stream or the sequence of signals may for example be arranged to be transferred via a data communication connection, for example via the Internet.

[0132] A further embodiment comprises a processing means, for example a computer, or a programmable logic device, configured to or adapted to perform one of the methods described herein.

[0133] A further embodiment comprises a computer having installed thereon a computer program for performing one of the methods described herein.

[0134] Further embodiments according to the invention include an apparatus or system configured to transfer (e.g. electronically or optically) a computer program for performing one of the methods described herein to a receiver. The receiver may be, for example, a computer, a mobile device, a memory device, etc. The apparatus or system comprises, for example, a file server for transferring the computer program to the receiver.

[0135] In some embodiments, a programmable logic device (e.g., a field programmable gate array) may be used to implement some or all of the functionality of the methods described herein. In some embodiments, a field programmable gate array may cooperate with a microprocessor to implement one of the methods described herein. In general, the methods are preferably implemented by any hardware apparatus.

[0136] The apparatus described herein may be implemented using a hardware apparatus, or using a computer, or using a combination of a hardware apparatus and a computer.

[0137] The methods described herein may be implemented using a hardware apparatus, or using a computer, or using a combination of a hardware apparatus and a computer. [Explanation of symbols]

[0138] 100 Driver circuit 110 Input Signal 120 Comparator 122 Control Signal 140 First voltage supply stage 142 First supply voltage 145 Charge Pump 150 Second voltage supply stage 152 Second Supply Voltage 160 Feedback Loop 162 Feedback Signal 180 Amplifier 182 Output Signal 200 Driver circuit 260 Feedback Loop 261 Voltage Dividers, Resistive Dividers 262 Feedback Signal 290 Load 300 Driver circuit 301 System 390 Load 402 Time Zone 403 hours 404 hours 5000 ways 6000 ways

Claims

1. A method (5000) for controlling a driver circuit (100, 200, 300), comprising: operating (5100) an amplifier (180) to provide an output signal (182) based on the control signal (122); operating (5200) a comparator (120) to provide the control signal (122) by comparing an input signal (110) with a feedback signal (162), the feedback signal (162) being based on the output signal (182); providing (5400) a first supply voltage (142) to the comparator (120) using a first charge pump stage; providing (5500) a second supply voltage (152) to the amplifier (180) using a second charge pump stage different from the first charge pump stage; Including, The second supply voltage (152) is higher than the first supply voltage (142). Method(5000).

2. The method of claim 1, wherein the amplitude of the control signal is lower than the amplitude of the output signal.

3. The method (5000) of claim 1 or 2, wherein the comparator (120) is operative to provide a continuous-time signal.

4. The method (5000) of claim 1 or 2, wherein the comparator (120) is operative to provide a discrete-time signal.

5. The method of claim 4, wherein the operating the comparator comprises self-clocking the comparator.

6. The method (5000) of any one of claims 1 to 5, wherein the input signal (110) and / or the output signal (182) are continuous in time.

7. The method (5000) of any one of claims 1 to 6, wherein the input signal (110) and / or the output signal (182) are discrete in time.

8. 8. The method (5000) of any one of claims 1 to 7, wherein the operating the amplifier (180) comprises operating a push-pull stage.

9. said operating said amplifier (180) comprising controlling at least one transistor of a first type and at least one transistor of a second type; the first type transistor and the second type transistor are complementary type transistors; 9. The method (5000) of any one of claims 1 to 8, wherein the first type transistor and the second type transistor are one of a FET, a power FET, or a bipolar junction transistor.

10. 10. The method of claim 9, wherein the operating the amplifier comprises controlling the at least one transistor of the first type to either a conductive state or a cutoff state and controlling the at least one transistor of the second type to the other state during each time instance of a first operating state.

11. A method (5000) according to any one of claims 1 to 10, further comprising the step of deriving the feedback signal (162) from the output signal (182) such that a ratio of an amplitude of the feedback signal (162) to an amplitude of the output signal (182) corresponds to an amplification factor of the driver circuit (100, 200, 300).

12. The first supply voltage (142) is at least 1 / 2, preferably at least 1 / 5, more preferably at least 1 / 10 of the second supply voltage (152).

12. The method (5000) according to any one of claims 1 to 11.

13. The first supply voltage (142) and / or the second supply voltage (152) are constant.

13. The method (5000) according to any one of claims 1 to 12.

14. and / or wherein the step of providing the first supply voltage (142) includes modulating the first supply voltage (142); and / or The step of providing the second supply voltage (152) includes modulating the second supply voltage (152).

13. The method (5000) according to any one of claims 1 to 12.

15. 15. The method (5000) of any one of claims 1 to 14, wherein the step of operating the amplifier (180) comprises the step of self-adjusting a maximum current conducted through a push-pull stage, the self-adjustment of the maximum current being based on a load.

16. A driver circuit (100, 200, 300), an amplifier (180) configured to provide an output signal (182) based on the control signal (122); a comparator (120) configured to provide the control signal (122) by comparing an input signal (110) with a feedback signal (162), the feedback signal (162) being based on the output signal (182) of the amplifier (180); Equipped with the comparator (120) is coupled to a first charge pump stage (140) configured to provide a first supply voltage (142) to the comparator (120); the amplifier (180) is connected to a second charge pump stage (150) configured to provide a second supply voltage (152) to the amplifier (180); The second supply voltage (152) is higher than the first supply voltage (142). Driver circuit (100, 200, 300).

17. 17. The driver circuit (100, 200, 300) of claim 16, wherein the amplitude of the control signal (122) is lower than the amplitude of the output signal (182).

18. 18. The driver circuit (100, 200, 300) of claim 16 or 17, wherein the comparator (120) is a discrete-time comparator or a continuous-time comparator.

19. 18. The driver circuit (100, 200, 300) of claim 16 or 17, wherein the comparator (120) is a discrete-time comparator, the comparator (120) being self-clocked.

20. A driver circuit (100, 200, 300) according to any one of claims 16 to 19, wherein the input signal (110) and / or the output signal (182) are continuous in time.

21. A driver circuit (100, 200, 300) according to any one of claims 16 to 20, wherein the input signal (110) and / or the output signal (182) are discrete in time.

22. 22. The driver circuit (100, 200, 300) of any one of claims 16 to 21, wherein the amplifier (180) comprises a push-pull stage.

23. the amplifier (180) comprises at least one transistor of a first type and at least one transistor of a second type; the first type transistor and the second type transistor are complementary type transistors; The first type transistor and the second type transistor are one of a FET, a power FET, or a bipolar junction transistor. A driver circuit (100, 200, 300) according to any one of claims 16 to 22.

24. 24. The driver circuit (100, 200, 300) of claim 23, configured to control, during each time instance of a first operating state, the at least one transistor of the first type to either a conductive state or a cut-off state and to control the at least one transistor of the second type to the other state.

25. a feedback loop configured to derive the feedback signal (162) from the output signal (182); The ratio of the amplitude of the feedback signal (162) to the amplitude of the output signal (182) corresponds to the amplification factor of the driver circuit (100, 200, 300). A driver circuit (100, 200, 300) according to any one of claims 16 to 24.

26. The first supply voltage (142) is at least 1 / 2, preferably at least 1 / 5, and more preferably at least 1 / 10 of the second supply voltage (152). A driver circuit (100, 200, 300) according to any one of claims 16 to 25.

27. The first supply voltage (142) and / or the second supply voltage (152) are constant. A driver circuit (100, 200, 300) according to any one of claims 16 to 26.

28. the first charge pump stage (140) is configured to modulate the first supply voltage (142); and / or The second charge pump stage (150) is configured to modulate the second supply voltage (152). A driver circuit (100, 200, 300) according to any one of claims 16 to 26.

29. 29. The driver circuit (100, 200, 300) of any one of claims 16 to 28, wherein the amplifier (180) is configured to self-adjust a maximum current conducted through a push-pull stage, the self-adjustment of the maximum current being based on a load.

30. The driver circuit (100; 200; 300) according to any one of claims 16 to 29, forming at least part of an integrated circuit.

31. A system (301), Load (290, 390) and A driver circuit (100, 200, 300) according to any one of claims 16 to 30; Equipped with The system is configured to control the load (290, 390) based on an output signal (182) of the driver circuit (100, 200, 300). System (301).

32. the system comprises an integrated circuit; The integrated circuit comprises the driver circuit (100, 200, 300). A system (301) according to claim 31.

33. the load (290, 390) includes a capacitance and / or an inductance; The resistance of the load (290, 390) is higher than 10 kOhm, or 100 kOhm, or 1 MOhm. A system (301) according to claim 31 or 32.

34. The system (301) of any one of claims 31 to 33, wherein the load (290, 390) comprises a MEMS actuator.

35. 34. The system (301) of any one of claims 31 to 33, wherein the load (290, 390) comprises a piezoelectric actuator.

36. The system (301) of any one of claims 31 to 33, wherein the load (290, 390) comprises a thermo-mechanical actuator.

37. The system (301) of any one of claims 31 to 33, wherein the load (290, 390) comprises an energy storage device.

38. 37. The system (301) of any one of claims 31 to 36, wherein the load (290, 390) comprises at least one of a loudspeaker, a microphone, a pump, a valve, a health assistance system, a positioning system, and a mechanical control for moving a plate.

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