Reference voltage selection method

Abstract

The invention discloses a reference voltage logic circuit, which is characterized by comprising a voltage comparison circuit, a reference voltage generation circuit and a reference voltage generation circuit, judging whether the voltages of all the feedback signals are higher than a first set voltage so as to determine the logic potential of an output point A and judging whether the voltage of at least one feedback signal is lower than a second set voltage so as to determine the logic potential of an output point B; the voltage selection logic circuit outputs a plurality of control signals according to the logic potentials of the output point A and the output point B; the voltage regulation logic circuit outputs a new reference voltage according to the plurality of control signals, when the voltages of all the feedback signals are higher than the first set voltage, the new reference voltage is lower than the old reference voltage, and when the voltage of at least one feedback signal is lower than the second set voltage VL, the new reference voltage is lower than the old reference voltage. The new reference voltage is higher than the old reference voltage, and the first set voltage is higher than the second set voltage.

Description

[0001] This application is a divisional application of the invention patent application with application number 202410920018.7. The filing date of the original application is July 10, 2024. Technical Field

[0002] The present application belongs to the field of driving circuits, and relates to a voltage driver that actively adjusts a feedback reference voltage under load current to improve efficiency. Background Art

[0003] Please refer to Figure 1 , which is a block diagram of a conventional driving circuit system 100. The driving circuit system 100 includes a driving circuit 110 and a constant current load circuit 120. The conventional driving circuit 110 includes a boost circuit 130 for increasing an input voltage V IN Boost to output voltage V OUT . Output voltage V OUT The voltage boost circuit 130 may include components such as a charge pump, a boost regulator, a DC-DC converter, or any combination of the above components. The selected oscillator 140 may be used to control the output voltage V OUT frequency.

[0004] The conventional driving circuit 110 includes a current regulator 150 after the constant current load circuit 120. The current regulator 150 outputs a feedback voltage V FB to the error amplifier (EA, error amplifier) ​​160 and the reference voltage V REF The error signal is input to the boost circuit 130. When the set output voltage V OUT When the voltage is greater than the starting voltage of the constant current load circuit 120 , the excess voltage will be across the current regulator 150 , resulting in power waste.

[0005] The constant current load circuit 120 may be one or more light emitting diodes (LEDs), and the driving circuit 110 may be a light emitting diode driving circuit. OUT The minimum required voltage is the on-state voltage of the light emitting diode. When applied to an existing LED display, the constant current load circuit 120 may include multiple strings of light emitting diodes.

[0006] Please refer to Figure 2 , which is a block diagram of another conventional driving circuit system 200. Figure 1 compared to, Figure 2 The load circuit is an LED display 220, which includes a plurality of (X) constant current load circuits 220-1 to 220-X, where X is a natural number greater than 1. Each constant current load circuit includes a plurality of light emitting diodes. Due to process variations, the starting voltages required by the constant current load circuits 220-1 to 220-X are usually different, some are higher and some are lower.

[0007] Since the starting voltage of each constant current load circuit varies, the feedback voltage V corresponding to the constant current load circuits 220-1 to 220-X is FB1 To V FBX The minimum voltage selection circuit included in the current regulator 250 will select the minimum voltage at multiple feedback voltages V FB1 To V FBX Choose the lowest V FB , and sends it to the error amplifier 160 and the reference voltage V REF The error signal is sent back to the boost circuit 130 for adjustment to obtain the best output voltage V OUT , so that the currents of the constant current load circuits 220-1 to 220-X can be as consistent as possible, thereby achieving stable and uniform brightness of the light-emitting diodes.

[0008] Figure 2 The driving circuit 210 may further include a pulse width modulation (PWM) control circuit 270, which may control the output voltage V OUT The pulse width, duty cycle or duty cycle.

[0009] Please refer to Figure 3 , which is a circuit diagram of an existing current regulator 350. The current regulator 350 is divided into a left and a right side. The right side is respectively connected to the aforementioned constant current load circuits 220-1 to 220-X, which respectively correspond to a plurality of feedback voltages V FB1 To V FBX The left side of the current regulator 350 is divided into two sides of the operational amplifier OPA_S. The left side of the operational amplifier OPA_S includes an external setting resistor R EXT The external reference current I REF The size corresponds to the external setting voltage V F With external setting resistor R EXT The ratio of is as shown in equation (1).

[0010]

[0011] The load current on the right side of the operational amplifier OPA_S is the external measured reference current I on the left side.REF N times. The reference voltage V for the load current setting on the right side of the operational amplifier OPA_S SET The load current on the right and the reference resistance R for setting the load current on the right SET The product of is shown in the following equation (2).

[0012] V SET =(N×I REF )×R SET Equation (2)

[0013] After substituting equation 1 into equation 2, equation (3) can be obtained.

[0014]

[0015] The outputs of the constant current load circuits 220-1 to 220-X on the right side of the current regulator 350 correspond to the resistors R1 to R X For the i-th load current I ld_i For example, equation (4) can be applied, where i is one of 1 to X.

[0016]

[0017] After substituting equation 3 into equation 4, equation (5) can be obtained.

[0018]

[0019] Based on this, the load current of each of the constant current load circuits 220-1 to 220-X can be obtained. By adjusting the external setting resistor R EXT , the required load current can be obtained. The total load current I load That is, each load current I ld_i The sum of i is 1 to X. If the brightness of the light-emitting diodes in the constant current load circuits 220-1 to 220-X is to be brighter, the external setting resistor R EXT On the contrary, if the brightness of the LEDs in the constant current load circuits 220-1 to 220-X is to be reduced, the external setting resistor R EXT value.

[0020] In addition, the aforementioned pulse width modulation (PWM) control circuit 270 can be used to control the output voltage V OUT By changing the pulse width, duty cycle or working ratio, the load current can be changed, and the brightness of the light-emitting diodes in the constant current load circuits 220-1 to 220-X can be further controlled.

[0021] Whether Figure 1 or Figure 2 The conventional driving circuits 110 or 210 shown in the figure both use the same fixed reference voltage V REF At different load currents I ld_i Under this condition, the driving circuit 110 or 210 still generates a fixed output voltage V OUT .

[0022] Please refer to Figure 4 As shown, it is Figure 2 The relationship between the load current and the corresponding starting voltage of the driving circuit system 200 is shown in FIG. The horizontal axis is the load current and the vertical axis is the voltage. When only the first constant current load circuit 220-1 is started, the required voltage is V L When all constant current load circuits 220-1 to 220-X are started, the required voltage is V H . V H Greater than V L .

[0023] from Figure 4 It can be seen that when the load current is small, its lowest feedback voltage V FB can be smaller. However, since the reference voltage V REF The voltage value is fixed. When the feedback voltage V FB When the reference voltage V REF In other words, the current regulator will be subjected to a larger voltage difference, resulting in unnecessary power consumption.

[0024] For example, a certain driving circuit system 200 has three constant current load circuits 220-i, where i is one of 1 to 3. Table 1 shows the three constant current load circuits 220-i under a fixed reference voltage V REF and the different load currents I caused by various start-up conditions load and minimum feedback voltage V FB Power consumption table.

[0025] <![CDATA[Load current I load > <![CDATA[Feedback voltage V FB > Power consumption 10mA 0.6V 6mW 20mA 0.6V 12mW 30mA 0.6V 18mW

[0026] Table 1: Different load currents and fixed reference voltage V REF The power consumption table of the generated cross voltage

[0027] In summary, there is a need for a system and method that can adaptively reduce the cross-voltage of a current regulator according to the load current, thereby reducing the extra power consumption. Summary of the invention

[0028] The present application proposes a reference voltage logic circuit and a reference voltage selection method to solve the deficiencies in the prior art, and aims to reduce the cross-voltage of the current regulator according to the load current adaptively, thereby reducing the extra power consumption, reducing the heat dissipation requirements, and increasing the service life of the logic circuit. If applied to portable mobile devices, it can also extend the use time under limited battery power supply.

[0029] In order to achieve the above purpose, this application adopts the following technical solutions:

[0030] According to an embodiment of the present application, a reference voltage logic circuit is provided, characterized in that it includes: a voltage comparison circuit for receiving at least one feedback signal and determining whether the voltage of all the feedback signals is higher than a first set voltage V H To determine the logic potential of the output point A and determine whether the voltage of at least one of the feedback signals is lower than the second set voltage V L to determine the logic potential of output point B; a voltage selection logic circuit, according to the logic potentials of output point A and output point B, outputs a plurality of control signals; and a voltage adjustment logic circuit, according to the plurality of control signals, outputs a new reference voltage, wherein when the voltage of all the feedback signals is higher than the first set voltage V H When the new reference voltage is lower than the old reference voltage, when at least one of the feedback signals has a voltage lower than the second set voltage V L , the new reference voltage is higher than the old reference voltage, wherein the first setting voltage V H Higher than the second set voltage V L .

[0031] Preferably, in order to determine only a single load current setting reference voltage V SET , characterized in that the voltage selection logic circuit is only based on the reference voltage V set by the load current SET As the only feedback signal, the reference voltage V SET The system is connected to the output of one or more constant current load circuits.

[0032] Preferably, in order to determine a plurality of feedback voltages, it is characterized in that the voltage selection logic circuit uses the outputs of a plurality of constant current load circuits as the plurality of feedback signals.

[0033] Preferably, in order to determine the logic potentials of the output point A and the output point B, the voltage comparison circuit further comprises: a plurality of hysteresis comparators; a logic circuit composed of more than one AND logic gate to output the logic potential of the output point A; and a logic circuit composed of more than one OR logic gate to output the logic potential of the output point B, wherein each of the plurality of feedback signals is related to the first setting voltage V H The result of one of the plurality of hysteresis comparators inputted is sent to the logic circuit composed of more than one AND logic gates, and each of the plurality of feedback signals is combined with the second setting voltage V L The result of one of the plurality of hysteresis comparators is sent to the logic circuit composed of the one or more OR logic gates.

[0034] Preferably, in order to be applicable to a light emitting diode screen, it is characterized in that the above-mentioned multiple constant current load circuits include multiple light emitting diodes connected in series.

[0035] According to one embodiment of the present application, a driving circuit is provided, characterized in that it includes: a reference voltage logic circuit as described above, used to output the aforementioned new reference voltage; a boost circuit, used to increase the input voltage to the output voltage according to the error signal; a current regulator, used to receive the outputs of the aforementioned multiple constant current load circuits so as to adjust the current and the output feedback voltage; and an error amplifier, used to receive the aforementioned new reference voltage and feedback voltage so as to output the error signal to the boost circuit.

[0036] According to an embodiment of the present application, a reference voltage selection method is provided, which includes: receiving one or more feedback signals; determining whether the voltage of all the feedback signals is higher than a first set voltage V H When the voltage of all the feedback signals is higher than the first set voltage V H , selecting a new reference voltage, wherein the new reference voltage is lower than the old reference voltage; determining whether at least one of the feedback signals has a voltage lower than the second set voltage V L When at least one of the feedback signals has a voltage lower than the second set voltage V L When the new reference voltage is higher than the old reference voltage; and when the voltage of at least one of the feedback signals is higher than the second set voltage V L and is lower than the first set voltage V H When the old reference voltage is selected, the first setting voltage V H Higher than the second set voltage V L .

[0037] Preferably, in order to determine only a single load current setting reference voltage V SET, characterized in that the reference voltage V SET As the only feedback signal mentioned above, the reference voltage V SET The system is connected to the output of one or more constant current load circuits.

[0038] Preferably, in order to determine a plurality of feedback voltages, the outputs of a plurality of constant current load circuits are used as the plurality of feedback signals.

[0039] Preferably, in order to be suitable for a light emitting diode screen, the plurality of constant current load circuits comprises a plurality of light emitting diodes connected in series.

[0040] Due to the adoption of the above scheme, the beneficial effects of the present application are: the voltage across the current regulator can be adaptively reduced according to the load current, which can reduce the extra power consumption, reduce the heat dissipation requirements, and increase the service life of the logic circuit. If applied to a portable mobile device, it can also extend the use time under the limited battery power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 is a block diagram of a conventional driving circuit system 100 .

[0042] Figure 2 FIG. 2 is a block diagram of another conventional driving circuit system 200 .

[0043] Figure 3 FIG. 3 is a circuit diagram of a conventional current regulator 350 .

[0044] Figure 4 for Figure 2 FIG. 2 is a diagram showing the relationship between the load current and the corresponding starting voltage of the driving circuit system 200 .

[0045] Figure 5 FIG. 5 is a circuit diagram of a driving circuit system 500 according to an embodiment of the present application.

[0046] Figure 6 FIG. 5 is a circuit diagram of a reference voltage logic circuit 580 according to an embodiment of the present application.

[0047] Figure 7 FIG. 7 is a circuit diagram of a driving circuit system 700 according to an embodiment of the present application.

[0048] Figure 8 FIG. 7 is a circuit diagram of a reference voltage logic circuit 780 according to an embodiment of the present application.

[0049] 9A to 9E FIG. 4 is a schematic diagram of logic potentials of output points A and B and multiple feedback voltages according to an embodiment of the present application.

[0050] Fig.10 FIG. 1 is a flow chart of a method 1000 for selecting a reference voltage according to an embodiment of the present application.

[0051] Fig.11 FIG. 1 is a flow chart of a method 1100 for selecting a reference voltage according to another embodiment of the present application.

[0052] Fig.12 It is a schematic diagram showing that the load circuit corresponds to different feedback voltages under different currents. DETAILED DESCRIPTION

[0053] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other implementation methods obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0054] The terms "first", "second", "third", etc. (if any) in the specification and claims of this application and the drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the objects described in these descriptions can be interchanged where appropriate. In the description of this application, "plurality" means two or more, unless otherwise clearly and specifically defined. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. Some of the block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in software form, or in one or more hardware circuits or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0055] In the description of the present application, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present application.

[0056] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two components or the interaction relationship between two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0057] In order to make the purpose, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below in conjunction with drawings and specific implementation methods.

[0058] Please refer to Fig.12 As shown in FIG. 1 , it is a schematic diagram of the load circuit corresponding to different feedback voltages under different currents. The load circuit mentioned above can be a circuit formed by one or more light-emitting diodes. If the load current set by the load circuit can be detected, the reference voltage V can be actively adjusted. REF , in order to obtain the best feedback voltage V FB , thereby reducing additional power consumption.

[0059] As mentioned above, the present application proposes a system and method that can adaptively reduce the cross-voltage of a current regulator according to the load current, so as to reduce the extra power consumption. The solution proposed in the present application is to detect one or more feedback voltages V FB Or the reference voltage V for load current setting SET , and dynamically adjust or set the reference voltage V according to the detection results REF Since the reference voltage V REF and one or more feedback voltages V FB Or the reference voltage V for load current setting SET The difference is small, which makes the boost circuit produce a lower output voltage V OUT , and by making the voltage regulator withstand a smaller cross-voltage, the additional power consumption of the driving circuit can be reduced.

[0060] Please refer to Figure 5 , which is a circuit diagram of a driving circuit system 500 according to an embodiment of the present application. Figure 5 The driving circuit system 500 includes Figure 2 and Figure 3 The current regulator 250 shown in the figure and the reference voltage logic circuit 580 which is one of the features of the invention. If there is no other special description, Figure 5 The descriptions of the components shown follow the previous descriptions.

[0061] from Figure 3 The current regulator 250 shown in FIG. 1 can be obtained from equation (3), the reference voltage V set by the load current SET The external setting resistor R EXT According to equation (5), the reference voltage V SET The load current I load Based on this, the reference voltage logic circuit 580 can detect the reference voltage V set by the load current. SET , to determine different load currents I load The corresponding reference voltage V REF , in order to generate the required output voltage V OUT .

[0062] When a smaller load current I is required load When the external setting resistor R EXT Increase so that the reference voltage V SET When the reference voltage V SET When the voltage becomes smaller, a lower reference voltage V REF , in order to output a lower output voltage V OUT Based on this, the feedback voltage V FB Close to or equal to the reference voltage V REF .

[0063] On the contrary, when a larger load current I is required load When the external setting resistor R EXT Reduce so that the reference voltage V SET When the reference voltage V SET When the voltage becomes larger, a higher reference voltage V REF , in order to output a higher output voltage V OUT Based on this, the feedback voltage V FB Close to or equal to the reference voltage V REF .

[0064] Please refer to Figure 6 FIG. 5 is a schematic diagram of a reference voltage logic circuit 580 according to an embodiment of the present application. The reference voltage logic circuit 580 may be applicable to Figure 5 In the driving circuit system 500 shown, the reference voltage logic circuit 580 may include a voltage comparison circuit 610, a voltage selection logic circuit 620, and a voltage adjustment circuit 630 in sequence.

[0065] The input of the voltage comparison circuit 610 includes the reference voltage VSET ,as well as Figure 4 The first set voltage V H and the second set voltage V L The voltage comparison circuit 610 includes an optional isolation buffer 613 (or buffer amplifier) ​​and two hysteresis comparators 611 and 612. The aforementioned reference voltage V SET The signals are output to two hysteresis comparators 611 and 612 respectively via an optional isolation buffer 613 .

[0066] Another input of the first hysteresis comparator 611 is a first set voltage V H When the load current sets the reference voltage V SET Greater than the first set voltage V H When the load current is set to the reference voltage V SET Less than the first set voltage V H When , the logic potential of output point A is 0.

[0067] Similarly, the other input of the second hysteresis comparator 611 is the second set voltage V L When the load current sets the reference voltage V SET Greater than the second set voltage V L When the load current is set to the reference voltage V SET Less than the second set voltage V L , the logic potential of output point B is 0.

[0068] The voltage adjustment circuit 630 may include X resistors and X switches, corresponding to Figure 5 The reference voltage VBG is input to the voltage adjustment circuit 630 via an isolation buffer. The voltage selection logic circuit 620 is used to generate the control signals of the X switches according to the logic potentials of the output points A and B. Figure 6 In the embodiment of , X can be set to 3. Although Figure 6 Only one logic circuit diagram of the voltage selection logic circuit 620 is provided, but a person skilled in the art can understand that there may be other different combinations of logic gates to output the control signals of X switches.

[0069] As mentioned above, the reference voltage V SET , to determine different load currents I load The corresponding reference voltage V REF , in order to generate the required output voltage V OUT . Reference voltage V for load current setting SETWith the load current I load When the load current I load The corresponding load current setting reference voltage V SET Greater than the maximum starting voltage V H When, therefore, an appropriate reference voltage V REF_Load_X , to adjust the output voltage V OUT , in order to obtain the appropriate feedback voltage V FB , reducing excess power consumption.

[0070] For convenience, the voltage comparison circuit 610 and the reference voltage V REF The output values ​​can be shown in Table 2:

[0071]

[0072] Table 2: Voltage comparison circuit 610 and reference voltage V REF Output table

[0073] Please refer to Table 3, which shows the different load currents of the three constant current load circuits 220-i and the Figure 5 and Figure 6 The selected reference voltage V of the embodiment shown is REF Compared with Table 1, the power consumption in Table 3 is reduced at lower load current.

[0074]

[0075]

[0076] Table 3: Different load currents and fixed reference voltage V REF The power consumption table of the generated cross voltage

[0077] Please refer to Figure 7 , which is a circuit diagram of a driving circuit system 700 according to an embodiment of the present application. Figure 7 The driving circuit system 700 includes a reference voltage logic circuit 780 which is one of the features of the invention. If there is no other special description, Figure 7 The descriptions of the components shown follow the previous descriptions. Figure 5 and Figure 6 Compared with the reference voltage logic circuit 580 shown in FIG. 1 , the reference voltage logic circuit 780 compares a reference voltage V set by a load current. SET , but multiple feedback voltages V FB1 To V FBX .

[0078] Please refer to Figure 8, which is a circuit diagram of a reference voltage logic circuit 780 according to an embodiment of the present application. The reference voltage logic circuit 780 can be applied to Figure 7 In the driving circuit system 700 shown, the reference voltage logic circuit 780 may include a voltage comparison circuit 810, a voltage selection logic circuit 820, and a voltage adjustment circuit 630 in sequence.

[0079] The input of the voltage comparison circuit 810 is X feedback voltages V FB1 To V FBX , and the aforementioned first set voltage V H and the second set voltage V L . X feedback voltage V FB1 To V FBX They come from X constant current load circuits 220-1 to 220-X respectively. Figure 6 As shown in the figure, each feedback voltage passes through two hysteresis comparators and the voltage V H and voltage V L When the feedback voltage is greater than the compared voltage V H or voltage V L When , the hysteresis comparator will output a logic potential of 1, otherwise, the hysteresis comparator will output a logic potential of 0.

[0080] The voltage comparison circuit 810 includes one or more AND logic gates 811 and one or more OR logic gates 812. The input includes a first set voltage V H The hysteresis comparator can connect its output to the AND logic gate 811, or connect its output to a tree structure composed of multiple AND logic gates. H , the logic potential of the output point A of the AND logic gate 811 or the tree structure composed of multiple AND logic gates will be 1; otherwise, as long as there is a feedback voltage less than the voltage V H When , the logic potential of the output point A of the AND logic gate 811 or the tree structure composed of multiple AND logic gates will be 0.

[0081] The input includes the second set voltage V L The hysteresis comparator can connect its output to the OR logic gate 812, or connect its output to a tree structure composed of multiple OR logic gates. L , the logic potential of the output point B of the OR logic gate 812 or the tree structure composed of multiple OR logic gates will be 1; on the contrary, when all X feedback voltages are greater than the second set voltage V L When , the logic potential of the output point B of the OR logic gate 812 or the tree structure composed of multiple OR logic gates will be 0.

[0082] The voltage selection logic circuit 820 may include more than one logic gate to control the voltage adjustment circuit 630 according to the logic potentials of the input points A and B. For convenience, the voltage comparison circuit 810 and the reference voltage V REF The output values ​​can be shown in Table 4:

[0083]

[0084] Table 4: Voltage comparison circuit 810 and reference voltage V REF Output table

[0085] Please refer to Fig. 9A and Fig. 9B , which is a schematic diagram of the logic potentials of output points A and B and multiple feedback voltages according to an embodiment of the present application. When the feedback voltage of any constant current load circuit is greater than the second set voltage V L and is less than the first set voltage V H When Fig. 9A and Fig. 9B The feedback voltage V FB1 and V FB2 , the logic potentials of the output points A and B are 0 and 1 respectively. At this time, the voltage selection logic circuit 820 will make the voltage adjustment circuit 630 select the original reference voltage V REF .

[0086] Please refer to Fig. 9C and Fig.9D , which is a schematic diagram of the logic potentials of output points A and B and multiple feedback voltages according to an embodiment of the present application. When the feedback voltage of any constant current load circuit is lower than the second set voltage V L When Fig. 9C and Fig.9D The V FB1 That is, lower than the second set voltage V L , the logic potentials of the output points A and B are 0 and 1 respectively. At this time, the voltage selection logic circuit 820 will make the voltage adjustment circuit 630 select a higher reference voltage V REF , in order to increase the output voltage V OUT .

[0087] Please refer to Fig.9E , which is a schematic diagram of the logic potentials of output points A and B and multiple feedback voltages according to an embodiment of the present application. When the feedback voltages of all X constant current load circuits are greater than the first set voltage V H , the logic potentials of the output points A and B are 1 and 0 respectively. At this time, the voltage selection logic circuit 820 will make the voltage adjustment circuit 630 select a reference voltage V REF, in order to reduce the output voltage V OUT .

[0088] Please refer to Fig.10 , which is a flow chart of a method 1000 for selecting a reference voltage according to an embodiment of the present application. The method 1000 for selecting a reference voltage can be used Figure 5 and Figure 6 The reference voltage logic circuit 580 shown or Figure 7 and Figure 8 The reference voltage selection method 1000 is implemented by the reference voltage logic circuit 780 shown in the figure. Those skilled in the art can understand that the reference voltage selection method 1000 can be implemented by using a combination of various logic circuits, and the present application does not limit the combination of logic circuits to the state disclosed by the reference voltage logic circuit 580 or the reference voltage logic circuit 780. In one embodiment, the reference voltage selection method 1000 can be implemented by using a signal processor and firmware commonly available on the market.

[0089] If there is no direct or indirect causal relationship between any two steps, the present application will not limit the execution order of the two steps. The reference voltage selection method 1000 starts with step 1010 .

[0090] Step 1010: Receive more than one feedback signal. Figure 5 and Figure 6 In the embodiment shown in FIG. 1 , step 1010 receives only one feedback signal, namely, the reference voltage V set by the load current. SET When applicable to Figure 7 and Figure 8 In the embodiment shown, step 1010 receives a plurality of feedback signals, namely, X feedback voltages V FB1 To V FBX . X feedback voltage V FB1 To V FBX They come from X constant current load circuits 220 - 1 to 220 -X respectively.

[0091] Step 1020: Determine whether the voltage of at least one of the feedback signals is lower than the second set voltage V L When at least one of the feedback signals has a voltage lower than the second set voltage V L When , the process proceeds to step 1030. Otherwise, the process may proceed to step 1040. In one embodiment, this step may depend on the logic potential of the output point B of the voltage comparison circuit.

[0092] Step 1030: Select a higher reference voltage. This step can be implemented using the aforementioned voltage selection logic circuit and voltage adjustment logic circuit.

[0093] Step 1040: Determine whether the voltage of all the feedback signals is higher than the first set voltage V H When the voltage of all the feedback signals is higher than the first set voltage V H When , the process proceeds to step 1050. Otherwise, the process may proceed to step 1060. In one embodiment, this step may depend on the logic potential of the output point A of the voltage comparison circuit.

[0094] Step 1050: Select a lower reference voltage. This step can be implemented using the aforementioned voltage selection logic circuit and voltage adjustment logic circuit.

[0095] Step 1060: Select the original reference voltage. This step can be implemented by using the aforementioned voltage selection logic circuit and voltage adjustment logic circuit.

[0096] Please refer to Fig.11 , which is a flow chart of a reference voltage selection method 1100 according to another embodiment of the present application. Fig.11 The reference voltage selection method 1100 and Fig.10 The reference voltage selection method 1000 shown in FIG. 1 is equivalent, and each step can be used in the same manner. Fig.10 The instructions are just to swap the order of some steps.

[0097] According to an embodiment of the present application, a reference voltage logic circuit is provided, characterized in that it includes: a voltage comparison circuit for receiving at least one feedback signal and determining whether the voltage of all the feedback signals is higher than a first set voltage V H To determine the logic potential of the output point A and determine whether the voltage of at least one of the feedback signals is lower than the second set voltage V L to determine the logic potential of output point B; a voltage selection logic circuit, according to the logic potentials of output point A and output point B, outputs a plurality of control signals; and a voltage adjustment logic circuit, according to the plurality of control signals, outputs a new reference voltage, wherein when the voltage of all the feedback signals is higher than the first set voltage V H When the new reference voltage is lower than the old reference voltage, when at least one of the feedback signals has a voltage lower than the second set voltage V L , the new reference voltage is higher than the old reference voltage, wherein the first setting voltage V H Higher than the second set voltage V L .

[0098] Preferably, in order to determine only a single load current setting reference voltage V SET , characterized in that the voltage selection logic circuit is only based on the reference voltage V set by the load current SETAs the only feedback signal, the reference voltage V SET The system is connected to the output of one or more constant current load circuits.

[0099] Preferably, in order to determine a plurality of feedback voltages, it is characterized in that the voltage selection logic circuit uses the outputs of a plurality of constant current load circuits as the plurality of feedback signals.

[0100] Preferably, in order to determine the logic potentials of the output point A and the output point B, the voltage comparison circuit further comprises: a plurality of hysteresis comparators; a logic circuit composed of more than one AND logic gate to output the logic potential of the output point A; and a logic circuit composed of more than one OR logic gate to output the logic potential of the output point B, wherein each of the plurality of feedback signals is related to the first setting voltage V H The result of one of the plurality of hysteresis comparators inputted is sent to the logic circuit composed of more than one AND logic gates, and each of the plurality of feedback signals is combined with the second setting voltage V L The result of one of the plurality of hysteresis comparators is sent to the logic circuit composed of the one or more OR logic gates.

[0101] Preferably, in order to be applicable to a light emitting diode screen, it is characterized in that the above-mentioned multiple constant current load circuits include multiple light emitting diodes connected in series.

[0102] According to one embodiment of the present application, a driving circuit is provided, characterized in that it includes: a reference voltage logic circuit as described above, used to output the aforementioned new reference voltage; a boost circuit, used to increase the input voltage to the output voltage according to the error signal; a current regulator, used to receive the outputs of the aforementioned multiple constant current load circuits so as to adjust the current and the output feedback voltage; and an error amplifier, used to receive the aforementioned new reference voltage and feedback voltage so as to output the error signal to the boost circuit.

[0103] According to an embodiment of the present application, a reference voltage selection method is provided, which includes: receiving one or more feedback signals; determining whether the voltage of all the feedback signals is higher than a first set voltage V H When the voltage of all the feedback signals is higher than the first set voltage V H , selecting a new reference voltage, wherein the new reference voltage is lower than the old reference voltage; determining whether at least one of the feedback signals has a voltage lower than the second set voltage V L When at least one of the feedback signals has a voltage lower than the second set voltage V L When the new reference voltage is higher than the old reference voltage; and when the voltage of at least one of the feedback signals is higher than the second set voltage V Land is lower than the first set voltage V H When the old reference voltage is selected, the first setting voltage V H Higher than the second set voltage V L .

[0104] Preferably, in order to determine only a single load current setting reference voltage V SET , characterized in that the reference voltage V SET As the only feedback signal mentioned above, the reference voltage V SET The system is connected to the output of one or more constant current load circuits.

[0105] Preferably, in order to determine a plurality of feedback voltages, the outputs of a plurality of constant current load circuits are used as the plurality of feedback signals.

[0106] Preferably, in order to be suitable for a light emitting diode screen, the plurality of constant current load circuits comprises a plurality of light emitting diodes connected in series.

[0107] The reference voltage logic circuit and reference voltage selection method provided by the present application can adaptively reduce the cross-voltage of the current regulator according to the load current, thereby reducing the extra power consumption, reducing the heat dissipation requirements, and increasing the service life of the logic circuit. If applied to a portable mobile device, it can also extend the use time under limited battery power supply.

[0108] The above is only a preferred specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can make equivalent substitutions or changes within the technical scope disclosed in the present application according to the technical solution and application concept of the present application, which should be covered by the protection scope of the present application.

Claims

1. A method for selecting a reference voltage, characterized in that: Include: receiving one or more feedback signals; Determine whether the voltage of all the feedback signals is higher than the first set voltage V H ; When the voltage of all the feedback signals is higher than the first set voltage V H , selecting a new reference voltage, wherein the new reference voltage is lower than the old reference voltage; Determine whether the voltage of at least one of the feedback signals is lower than the second set voltage V L ; When the voltage of at least one of the feedback signals is lower than the second set voltage V L , the new reference voltage is higher than the old reference voltage; and When the voltage of at least one of the feedback signals is higher than the second set voltage V L and is lower than the first set voltage V H When the old reference voltage is selected, The first set voltage V H Higher than the second set voltage V L .

2. The method for selecting a reference voltage according to claim 1, wherein: The load current sets the reference voltage V SET As the only feedback signal mentioned above, the reference voltage V SET The system is connected to the output of one or more constant current load circuits.

3. The method for selecting a reference voltage according to claim 1, wherein: The outputs of the multiple constant current load circuits serve as the multiple feedback signals mentioned above.

4. The method for selecting a reference voltage according to claim 3, wherein: The multiple constant current load circuits include multiple light emitting diodes connected in series.

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