This application claims the priority benefit of Taiwan application serial no. 101142075, filed on Nov. 12, 2012. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.
1. Field of the Invention
The invention generally relates to a voltage generation module and a voltage generation method thereof, and more particularly, to a charge pump module and a voltage generation method thereof.
2. Description of Related Art
An electronic circuit often needs various power supply voltages having different voltage levels, and thus a charge pump circuit is usually configured to use the existing power supply voltage to generate various power supply voltages of different voltage levels. The charge pump circuit generates the voltages of different levels by boosting (or bucking) the input voltage with a predetermined multiple. Therefore, the levels of the output voltage of the charge pump circuit are related to the input voltage.
However, in order to extend the applications of the charge pump circuit in various environments (i.e., the input voltage is uncertain when the charge pump circuit is designed) to generate the expected output voltages, the received input voltage is usually first detected by utilizing a voltage detection circuit, and a predetermined boost ratio is determined accordingly, such that the level of output voltage is adjusted to a rated voltage, and then a rated output voltage is generated by the charge pump. The boost ratio determined by such method may only be selected from many predetermined ratios, and unable to adjust the boost ratio according to the practical design requirement. Therefore, the rated output voltage may be higher than a voltage that is required for the circuit of the next stage, and thus it may waste on more power.
Accordingly, the disclosure is directed to a charge pump module that can adaptively adjust its boost ratio to reduce power consumption.
The disclosure is directed to a voltage generation method of a charge pump module that can adaptively adjust a boost ratio of the charge pump module to reduce power consumption.
The disclosure provides a charge pump module including a ratio control circuit and a charge pump circuit. The ratio control circuit is configured to provide a boost ratio according to a control signal. The ratio control circuit includes at least two ratio generation circuits having different boost ratios. In addition, the ratio control circuit dynamically switches between the ratio generation circuits to adjust the boost ratio provided by the ratio control circuit. The charge pump circuit is coupled to the ratio control circuit. The charge pump circuit is configured to receive an input voltage and convert the input voltage into an output voltage according to the boost ratio provided by the ratio control circuit.
According to an embodiment of the disclosure, the control signal includes a first period and a second period. During the first period, the ratio control circuit switches to one of the ratio generation circuits. During the second period, the ratio control circuit switches to another one of the ratio generation circuits.
According to an embodiment of the disclosure, the charge pump module further comprises a voltage detection circuit. The voltage detection circuit is coupled to the charge pump circuit and the ratio control circuit. The voltage detection circuit detects the output voltage, and accordingly provides the control signal to the ratio control circuit.
According to an embodiment of the disclosure, the control signal includes a first period and a second period. The voltage detection circuit compares the output voltage with a first threshold value and a second threshold value to determine a duty cycle of the first period and the second period of the control signal.
According an embodiment of the disclosure, the first threshold value is greater than the second threshold value. According to a detection result of the voltage detection circuit, if the output voltage is less than the second threshold, the ratio control circuit switches to one of the ratio generation circuits having a higher boost ratio according to the control signal. If the output voltage is greater than the first threshold value, the ratio control circuit switches to one of the ratio generation circuits having a lower boost ratio according to the control signal.
According to an embodiment of the disclosure, the first threshold value and the second threshold value is determined according to a predetermined target value of the output voltage.
According to an embodiment of the disclosure, the ratio control circuit further includes a ratio selection circuit. The ratio selection circuit is coupled to the ratio generation circuits. The ratio selection circuit is configured to dynamically switch to one of the ratio generation circuits.
According to an embodiment of the disclosure, the boost ratio of the ratio generation circuits is negative. In addition, the charge pump circuit provides the negative output voltage according to the negative boost ratio provided by the ratio control circuit.
According to an embodiment of the disclosure, the boost ratio of the ratio generation circuits is positive. In addition, the charge pump circuit provides the positive output voltage according to the positive boost ratio provided by the ratio control circuit.
According to an embodiment of the disclosure, the boost ratio provided by the ratio control circuit is between the maximum boost ratio and the minimum boost ratio of the switched generation circuits.
Accordingly, the disclosure is directed to a voltage generation method of a charge pump module. The charge pump module includes a ratio control circuit and a charge pump circuit. The ratio control circuit includes at least two ratio generation circuits having different boost ratios. The voltage generation method includes the following steps. According to a control signal, a boost ratio outputted to the charge pump circuit is adjusted by dynamically switching between the ratio generation circuits. According the boost ratio outputted to the charge pump circuit, an input voltage is converted into an output voltage.
According to an embodiment of the disclosure, the control signal includes a first period and a second period, and the step of dynamically switching between the ratio generation circuits includes the following steps. During the first period, one of the ratio generation circuits is switched according to the control signal. During the second period, another one of the ratio generation circuit is switched to according to the control signal.
According to an embodiment of the disclosure, the voltage generation method further includes a step of detecting the output voltage and accordingly providing the control signal.
According to an embodiment of the disclosure, the control signal includes a first period and a second period. The step of detecting the output voltage and accordingly providing the control signal includes a step of comparing the output voltage with a first threshold value and a second threshold value to determine a duty cycle of the first period and the second period of the control signal.
According to an embodiment of the disclosure, the first threshold value is greater than the second threshold value. The step of comparing the output voltage with the first threshold value and the second threshold value includes the following steps. If the output voltage is less than the second threshold value, one of the ratio generation circuits having a higher boost ratio is switched according to the control signal. If the output voltage is greater than the first threshold value, one of the ratio generation circuits having a lower boost ratio is switched according to the control signal.
According to an embodiment of the disclosure, the first threshold value and the second threshold value are determined according to a predetermined target value of the output voltage.
According to an embodiment of the disclosure, the boost ratio of the ratio generation circuits is negative value, and in the step of converting the input voltage into the output voltage, the negative output voltage is provided according to the negative boost ratio outputted to the charge pump circuit.
According to an embodiment of the disclosure, the boost ratio of the ratio generation circuits is positive value, and in the step of converting the input voltage into the output voltage, the positive output voltage is provided according to the positive boost ratio outputted to the charge pump circuit.
According to an embodiment of the disclosure, the boost ratio outputting to the charge pump circuit is between the maximum boost ratio and the minimum boost ratio of the switched ratio generation circuits.
In the view of above, in the exemplary embodiments of the disclosure, the charge pump module dynamically switches between various boost ratios, so as to adaptively adjust an equivalent ratio value that is between the switched ratios.
In order to make the aforementioned and other features and advantages of the invention comprehensible, several exemplary implementations accompanied with figures are described in detail below.
The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the disclosure and, together with the description, serve to explain the principles of the disclosure.
Reference will now be made in detail to the present preferred embodiments of the disclosure, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.
In the example, a voltage detection circuit 120 detects the amount of the input voltage Vin as a basis for the switching ratio of a ratio selection module 130. Under the operation of the input voltage Vin having higher voltage, the ratio selection module 130 switches to a ratio generation circuit having a lower ratio, which satisfies the requirement of the output voltage Vout as well as conserves power. On the contrary, under the operation of the input voltage Vin having a lower voltage, the ratio selection module 130 switches to a ratio generation circuit having a higher ratio in order to satisfy the voltage requirement of the output voltage Vout. For example, when the output voltage Vout is within a range of 3.7 volt to 4.5 volt, the ratio selection module 130 is switched to a ratio generation circuit 134_1. When the output voltage is within a range of 3 volt to 3.7 volt, the ratio selection module 130 switches to a ratio generation circuit 134_2. When the output voltage is within a range of 2.5 volt to 3 volt, the ratio selection module 130 switches to a ratio generation circuit 134_4. When the output voltage is 2.5 volt or below, the ratio selection module 130 switches to a ratio generation circuit 134_4.
Therefore, in order to satisfy the requirements described above, the ratio selection module 130 may includes four ratio generation circuits having different ratios 134_1 thru 134_4, that is, X1.5, X2, X2.5, and X3, so as to provide various selections of different ratios. According to the maximum load current required by the output terminal, a ratio selection circuit 132 of the ratio selection module 130 determines which one of the ratios is to select with respect to the amount of the input voltage Vin, so as to attain the required output voltage Vout, and the selected ratio determines the current consumption. However, this type of design is unable to switch the ratio in accordance with different load current variations, in order to satisfy the requirement of power conservation. That is, the charge pump module 100 selects a ratio out of some fixed ratios, and unable to adjust the required boost ratio according to the amount of input voltage and the amount of the load current, which creates an input current that is equal to the load current multiply by the boost ratio, and generating excessive current consumption. Furthermore, while designing a different ratio generation circuit, it requires different circuit configurations so as to obtain the desired boost ratios. Therefore, more ratio selection increases the design complexity of the charge pump circuit, the layout area occupied by the circuit, and reduces the driving ability of the charge pump.
In the exemplary embodiments of the disclosure, the charge pump module dynamically switches between various boost ratios according to the control signal, so as to generate a ratio value equivalent to a ratio between the switched boost ratios. In an embodiment, the charge pump can auto adjust the ratio by detecting the voltage level of output voltage, so as to conserve power. In order to make the embodiments of the disclosure comprehensible, at least one embodiment accompanying with figures is described in detail below.
In the present embodiment, the adjustment of the boost ratio is to switch between the ratio generation circuits 222_1 and 222_2 through a time-sharing setting, so as to attain the driving capability and the power consumption equivalent to a boost ratio between the boost ratios of the ratio generation circuits 222_1 and 222_2.
In the above embodiment, the boost ratios X1.5 and X2.5 of the ratio generation circuits 222_2 and 222_2 are positive values. The charge pump circuit 210 provides the positive output voltage Vout according the positive boost ratio Sbr provided by the ratio control circuit 220, however, the concept of the ratio adjustment described in the disclosure is not limited to the charge pump circuit 210 that provides a positive voltage. The disclosure may also be applied to a charge pump circuit that provides a negative voltage.
It should be noted that, in the embodiments illustrated in
Furthermore, the voltage generation method of the embodiment of the disclosure is sufficiently taught, suggested, and embodied in the embodiments illustrated in
In the disclosure, there are various methods for the charge pump module to configure and adjust the timing of the control signal Sctrl, where one of the embodiments may be implemented by detecting the output voltage Vout.
In the present embodiment, according to a detection result of the voltage detection circuit 630, if the output voltage Vout is less than the second threshold value VL, the ratio control circuit 620 switches to the ratio generation circuit having a higher boost ratio according to the control signal Sctrl, such as switching to the ratio generation circuit 622_2 having the ratio of X2.5. On the contrary, if the output voltage Vout is greater than the first threshold VH, the control circuit 620 switches to the ratio generation circuit having a lower boost ratio according to the control signal Sctrl, such as switching to the ratio generation circuit 622_1 having the ratio of X1.5. According to a simulation result, under the operation of such circuit configuration having a current load of 14 mA, the proportion of time (i.e., duty cycle) occupied by the second period T2, i.e., switched to the ratio of X1.5, is greater than the first period T1, i.e., switched to the ratio of X2.5. Under the operation while the current load is 26 mA, the proportion of time (i.e., duty cycle) occupied by the first period T1, i.e., switched to the ratio of X2.5, is greater than the second period T2, i.e., switched to the ratio of X1.5. Furthermore, in the exemplary embodiment of the disclosure, the first threshold value VH and the second threshold value VL are determined according to a predetermined target value of the output voltage Vout. In the example, the first threshold value VH is configured to 5.5 volt, and the second threshold value VL is configured to 5 volt, however, the disclosure is not limited thereto.
The voltage detection circuit 630 of the embodiment detects the output voltage Vout, and the charge pump circuit 610 configures the first threshold value VH as the maximum voltage of the output voltage Vout and the second threshold VL as the minimum voltage of the output voltage Vout, where the second threshold value VL can be configured as the minimum voltage of the application requirement. When the output voltage Vout is lower than the second threshold value VL, which representing the voltage multiplying capability of the ratio at that moment is unable to satisfy the application requirement, the ratio control circuit 620 switches to a higher boost ratio at the next timing cycle. On the contrary, when the output voltage Vout is higher than a predetermined value of the first threshold value VH, the ratio control circuit 620 switches to a lower boost ratio at the next timing cycle, so as to reduce power consumption.
Such concept of configuring the control signal Sctrl by detecting the output voltage is not limited to the charge pump circuit 610 providing the positive voltage. It may be applied to a charge pump circuit providing a negative voltage as well.
Alternatively, the ratio control circuit may be implemented with four ratio generation circuits having different ratios X1.5, X2, X2.5 and X3, and the charge pump module may utilize the voltage detection circuit to detect the amount of voltage, so as to switch between the four ratios dynamically. Since, the voltage level of the output voltage reflects a size of the present load current, the ratio control circuit may dynamically auto adjust the ratio corresponding to different load currents, so as to achieve the purpose of power conservation.
Furthermore, the voltage generation method of the embodiment of the disclosure is sufficiently taught, suggested, and embodied in the embodiments illustrated in
In summary, in the exemplary embodiments of the disclosure, the charge pump module switches between various boost ratios dynamically, so as to produce a ratio value equivalent to a ratio between the switched ratios. Furthermore, the charge pump module may also detect the voltage level of the output voltage to automatically adjust the ratio.
It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the disclosure without departing from the scope or spirit of the disclosure. In view of the foregoing, it is intended that the disclosure cover modifications and variations of this disclosure provided they fall within the scope of the following claims and their equivalents.
Number | Date | Country | Kind |
---|---|---|---|
101142075 | Nov 2012 | TW | national |