Patent Grant
8310215
1. Technical Field
The present invention relates to a linear modulation voltage transformer circuitry and, more particularly, to a linear modulation voltage transformer configured for real-time voltage transformation.
2. Description of Related Art
Voltage transformers serve to convert an input power, such as an input current, into an output power of a certain specification, such as a specific output voltage. For example, a common analog voltage transformer typically uses two voltage divider resistors to step down an input voltage to a specific or a predetermined voltage.
Please refer to
As shown in
The power stage unit 30 is configured for step-up, step-down, and step-up/down voltage conversion so as to convert an input voltage 20 into an output voltage of a certain specification.
The voltage division unit 40 is connected to the power stage unit 30 and includes two voltage divider resistors. The voltage division unit 40 can use different voltage divider resistors to divide the input voltage 20 at different ratios according to the voltage specification of a load circuit and then outputs a divided voltage VR to the error amplifier 50.
The error amplifier 50, which includes a first impedance 51, a second impedance 52, and an amplifier 53, receives the divided voltage VR, compares the divided voltage VR with a reference voltage VRef, amplifies the voltage difference therebetween, and outputs an error gain control signal EGS to the recursive controller 60. The error gain control signal EGS serves as a basis on which the power stage unit 30 determines whether to perform step-up, step-down, or step-up/down voltage conversion.
The recursive controller 60 is a pulse width modulator 61 for modulating the pulse width of the error gain control signal EGS, generating a gain control signal GCS suitable for the power stage circuit, and outputting the gain control signal GCS to the power stage unit 30. Therein, a check voltage VMag is a necessary parameter for pulse width modulation of the error gain control signal EGS.
As shown in
Presently, the conventional voltage transformer 10 is applicable only to load circuits of a certain voltage specification. If it is desired to apply the voltage transformer 10 to load circuits of different voltage specifications, the output voltage of the voltage transformer 10 must be varied.
One common solution to varying the output voltage of the conventional voltage transformer 10 is to use a variable resistor as the voltage division unit 40. However, the disadvantage of using the variable resistor is that the resistance must be manually adjusted, which may result in over-adjustment and subsequent damage to the circuit, and that real-time adjustment is unattainable.
Another common solution is to change the reference voltage VRef and thereby change the error gain control signal EGS output from the error amplifier 50. Since the reference voltage VRef of an analog circuit is built-in to the circuit in advance and therefore unchangeable, this solution is applicable only to a digital voltage transformer. However, once the circuit is burned into an IC, all the divided voltages are fixed; hence, it is impossible to change the output voltage by varying the reference voltage VRef.
It is an objective of the present invention to provide a linear modulation voltage transformer circuitry which, due to the provision of a linear modulation unit, is applicable to load circuits of various voltage specifications and capable of real-time adjustment of its output voltage in accordance with the desired voltage specification.
It is another objective of the present invention to provide a linear modulation voltage transformer circuitry which, due to the provision of a linear modulation unit, can generate a linear voltage difference signal in order to output a linearly modulation voltage.
To achieve the above objectives, the present invention provides a linear modulation voltage transformer circuitry which includes: a power stage unit for receiving and adapting an input voltage and outputting a first voltage; a voltage division unit electrically connected to an output end of the power stage unit and configured to receive the first voltage and output a divided voltage; a linear modulation unit for receiving the divided voltage and a control voltage and outputting an error voltage signal; an error amplifier for receiving the error voltage signal as a reference voltage and comparing the divided voltage with the reference voltage so as to generate an error gain control signal; and a recursive controller for receiving the error gain control signal and outputting a gain control signal to the power stage unit so as for the power stage unit to modulate the first voltage.
Implementation of the present invention involves at least the following inventive steps:
1. The linear modulation voltage transformer circuitry with the linear modulation unit features a highly adaptive output voltage and therefore is applicable to load circuits of various voltage specifications.
2. When the load circuit is changed, the linear modulation voltage transformer circuitry with the linear modulation unit can perform step-up, step-down, and step-up/down voltage conversion in keeping with the voltage specification of the load circuit without having to modify the linear modulation voltage transformer circuitry itself, thus broadening the range of load circuits to which the linear modulation voltage transformer circuitry is applicable.
3. The linear modulation unit allows a secondary current converter circuit to be used invariably; in other words, there is no need to change the secondary current converter circuit when the load circuit is changed.
A detailed description of further features and advantages of the present invention is given below so that a person skilled in the art can understand and implement the technical contents of the present invention and readily comprehend the objectives and advantages thereof by reference to the disclosure of the present specification and the appended claims in conjunction with the accompanying drawings, in which:
Referring to
The power stage unit 30 receives an input voltage 20, adapts the received input voltage 20, and outputs a first voltage V1. The power stage unit 30 is capable of step-up, step-down, and step-up/down voltage conversion.
The voltage division unit 40, which is electrically connected to an output end of the power stage unit 30, receives the first voltage V1 and outputs a divided voltage VR. The voltage division unit 40 includes two voltage divider resistors, namely a first resistor R1 and a second resistor R2. The first resistor R1 and the second resistor R2 are connected in series between the output end of the power stage unit 30 and a ground end. A divided voltage output end for outputting the divided voltage VR is the node between the first resistor R1 and a second resistor R2.
The linear modulation unit 70 receives the divided voltage VR and a control voltage VCtrl and outputs an error voltage signal EVS, wherein the control voltage VCtrl is at a preset voltage level. More specifically, the linear modulation unit 70 includes an impedance matching unit 71 and an adder 72.
Referring also to
The adder 72 generates the error voltage signal EVS by summing the first signal S1 and the second signal S2. The adder 72 is composed of an operational amplifier 721, whose inverting positive input end is further connected with a third resistor R3 and a fourth resistor R4, thereby providing the aforesaid input end of the adder 72 with a voltage stabilizing and voltage following function.
Referring to
With reference to
The recursive controller 60 receives the error gain control signal EGS and a check voltage VMag and outputs a gain control signal GCS to the power stage unit 30 so as for the power stage unit 30 to modulate the first voltage V1. The recursive controller 60 is a pulse width modulator 61, and the gain control signal GCS is a pulse width modulation signal. By modulating the pulse width of the error gain control signal EGS, the recursive controller 60 generates the gain control signal GCS that is suitable for being output to the power stage unit 30. The gain control signal GCS serves as a basis on which the power stage unit 30 determines whether to perform step-up, step-down, or step-up/down conversion on the first voltage V1. The check voltage VMag is a parameter needed in modulating the pulse width of the error gain control signal EGS.
The control principle is demonstrated by the following examples:
Case 1: When the control voltage VCtrl is preset at 0, and a pre-arranged load circuit has a load voltage of 2.5V, the divided voltage VR output from the voltage division unit 40 is the reference voltage VRef (VRef=VR). As the load voltage increases, the reference voltage VRef rises linearly with the load voltage (VRef=VR>2.5V). Consequently, the error amplifier 50 transmits a voltage regulating signal to the recursive controller 60, forcing the divided voltage VR of the voltage division unit 40 to drop to a normal level (VRef=VR=2.5V).
When the load voltage decreases, the reference voltage VRef declines linearly with the load voltage. As a result, the error amplifier 50 transmits a voltage regulating signal to the recursive controller 60, and the divided voltage VR of the voltage division unit 40 is raised to the normal level (VRef=VR=2.5V). Thus, the linear modulation voltage transformer circuitry 100 remains stable when the control voltage VCtrl is 0.
Case 2: When the control voltage VCtrl is preset at a positive level, it can be known from Case 1 that the divided voltage VR output from the voltage division unit 40 will follow the voltage of the load circuit and be linearly adjusted. Hence, the equation of VRef=VR±VCtrl is obtained, meaning that the reference voltage VRef not only varies with the load voltage, but also has a voltage increment equal to the control voltage VCtrl ((VRef=2.5V±VCtrl)>2.5V). Once a voltage lowering signal is transmitted to the recursive controller 60, linear voltage reduction is carried out.
Case 3: When the control voltage VCtrl is preset at a negative level, it can be known from Case 1 that the divided voltage VR output from the voltage division unit 40 will follow the load voltage and be linearly adjusted. Hence the equation of VRef=VR+(−VCtrl) is obtained, meaning that the reference voltage VRef not only varies with the load voltage, but also is lowered by a magnitude equal to the control voltage VCtrl ((VRef=2.5V+(−VCtrl))<2.5V). Once a voltage raising signal is sent to the recursive controller 60, a linear voltage raising process begins.
Referring to
In contrast to the conventional voltage transformer, the linear modulation voltage transformer circuitry 100 exhibits excellent adaptability. In particular, the linear modulation unit 70 allows the linear modulation voltage transformer circuitry 100 to be used with load circuits of various voltage specifications without having to connect with additional voltage transformers. Furthermore, when the load circuit is changed, the linear modulation voltage transformer circuitry 100 can perform step-up, step-down, or step-up/down voltage conversion in real time to follow the voltage specification of the load circuit, without having to modify the circuitry 100 itself.
The embodiments described above serve to demonstrate the features of the present invention so that a person skilled in the art can understand the contents disclosed herein and implement the present invention accordingly. The embodiments, however, are not intended to limit the scope of the present invention, which is defined only by the appended claims. Therefore, all equivalent changes or modifications which do not depart from the spirit of the present invention should fall within the scope of the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 98146158 A | Dec 2009 | TW | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 4347474 | Brooks et al. | Aug 1982 | A |
| 5471131 | King et al. | Nov 1995 | A |
| 6181120 | Hawkes et al. | Jan 2001 | B1 |
| 6774612 | Ballenger et al. | Aug 2004 | B1 |
| 7724546 | Kusubayashi | May 2010 | B2 |
| Number | Date | Country | |
|---|---|---|---|
| 20110156665 A1 | Jun 2011 | US |
