KR100341705B1 - Method, device, control circuit for power synchronization - Google Patents

Abstract

The power supplies 1 and 2 are synchronized to the repetition frequency of the line addressing in the multi-scan rate line addressing circuit 7. The power supplies 1 and 2 work well when switched within the specified frequency range. The switching frequency of the power sources 1 and 2 is equal to the repetition frequency divided by an integer greater than zero. The constant is determined so that the switching frequency of the power supply 1, 2 occurs within the frequency range specified for all repetition frequencies of the line addressing.

Description

Method, device, control circuit for power synchronization

Synchronous power supplies for such multiple scan frequency video monitors are known from US Pat. No. 4,516,169. Known display systems describe horizontal deflection circuits operable with two selectable horizontal deflection frequencies. The switching power supply is switched at one optimal switching frequency synchronized to the selected horizontal deflection frequency, depending on one of the two horizontal deflection frequencies. Because of the synchronized operation of the switching power supply, it is desirable to prevent the switching components in the switching power supply from being visible on the water tube of the display system. The known display system shows one embodiment that can cope with two different horizontal deflection frequencies, wherein the first horizontal frequency is 15.75 KHz and the second horizontal frequency is 31.5 KHz, which is twice the first horizontal frequency. The switching power supply is operated on a first horizontal frequency of l5.75 KHz for the two horizontal deflection frequencies. A disadvantage of known display systems is that only a fixed switching frequency of the switching power supply synchronized to two horizontal deflection frequencies is possible when each horizontal deflection frequency is an integer multiple of the fixed switching frequency. The display system does not provide a practical solution if the known display system must be able to display horizontal deflection frequencies rather than an integer multiple of one fixed frequency suitable for switching the switching power supply. This may be the case in computer monitors where the horizontal deflection frequencies may be 35.2, 37.8, 48, 56, 64, 77.1, or 81.1 KHz, respectively.

The present invention relates to a method, an apparatus, and a control circuit for synchronizing power to a line addressing repetition frequency of a line addressing circuit, the method comprising: generating a trigger moment having a trigger repetition frequency equal to the line addressing repetition frequency; And determining an integer greater than zero in accordance with the trigger repetition frequency, and generating a control moment in response to the trigger moment to determine a switching frequency of the power source, wherein the control moment is divided by the integer. It has a repetition frequency which is a trigger repetition frequency.

Such methods and control circuits for power synchronization are applicable to display systems including multiple scan rate circuits and image display devices suitable for displaying images with different scan rates as in the case of computer monitors. The power supply may be used to supply a stable voltage to other circuits of the display system or to generate an anode voltage for an image display device.

1 shows an embodiment of a display system according to the invention.

2A-2D show certain signals to illustrate the operation of a control circuit according to the invention as shown in FIG.

EXAMPLE

The above and other aspects of the invention are described in more detail by way of examples in conjunction with the accompanying drawings.

1 shows an embodiment of a display system according to the invention. The synchronization circuit 5 receives the image signal Pi and supplies the line and frame synchronization signals Vs and Hs to the addressing circuit 7. The addressing circuit 7 includes a line addressing circuit for generating a line deflection current through the line deflection coil Lh in response to the line synchronization signal Hs, and a frame deflection coil Lv in response to the frame synchronization signal Vs. And a frame addressing circuit for generating a frame deflection current. The line addressing circuit generates a trigger signal St having a repetition frequency equal to the repetition frequency of the line deflection current or the repetition frequency of the line synchronization signal Hs. The first power source 1 receives an unstabilized input voltage Vac-for example, an AC mains voltage-to a second power source 2 that is an EHT power source that supplies the anode voltage Va to the water pipe 4. Supply a stabilized output voltage (Vb). The first power source 1 and the EHT power source 2 are controlled by respective control signals Sc1 and Sc2. Control signals Sc1 and Sc2 determine the switching frequency of each power source 1,2. The control circuit 6 receives the trigger signal St and supplies the control signals Sc1 and Sc2. The control circuit 6 includes two non-recurable monostable multivibrators (eg, National Semiconductor's MM74HC221A) 60, 61. The two multivibrators 60 and 61 have a negative transition trigger input A connected to a low level L, a positive transition trigger input B for receiving a trigger signal St, and a high ( There is a clear input (CLR) connected to the high level (H). The first multivibrator 60 has an output Q1 for supplying a first control signal Sc1. The second multivibrator 61 has an output Q2 for supplying a second control signal Sc2. The multivibrators 60, 61 exhibit a suppression state during the suppression period because of the positive leading edge of the trigger signal St. Each deactivation period has a duration corresponding to the highest frequency at which the corresponding power source 1, 2 can be operated. Since both the multivibrators 60 and 61 operate in the same manner, only the operation of the first multivibrator 60 is described. The trigger signal St that occurs during the suppression period has no effect when the first multivibrator 60 is untriggered. Output signal Q1 goes high during its suppression period. The rising edge of the output signal Q1 contains repetitive frequency information for controlling the first power source 1.

Operation of the multivibrator 60 is further described with reference to FIGS. 2A-2D. For example, since the highest switching frequency of the first power source 1 is selected to 60 KHz, the duration of the suppression period Td should be 16.7 kHz. 2A to 2D show the operation of the multivibrator 60 in the trigger signal St having repetition frequencies of 15 KHz, 50 KHz, 70 KHz and 200 KHz, respectively. Only the moment of the relevant operating state of the trigger signal St is shown. The control signal Sc which determines the switching frequency of the first power source 1 is related to the rising edge of the output signal Q1.

2A and 2B, the trigger signal St in the operating state at the moment t0 is the multivibrator 60 in the suppression state in which the output signal Q1 has a high level during the suppression period Td up to the moment t1. Trigger When the next trigger signal St occurs at the moments t2 and t2 'after the moment tl (the trigger signal St has a repetition frequency within a prescribed frequency range), each trigger signal St is It will trigger the suppression cycle. At each trigger of the suppression period, the control signal Sc is generated to obtain the switching frequency of the first power supply 1, such as the line frequency, which is 15 KHz and 50 KHz, respectively.

Also in FIGS. 2C and 2D, the trigger signal St in the operating state at the moment t0 is a suppressor state in which the output signal Q1 has a high level such as the suppression period Td up to the moment t1. Trigger). All trigger signals St generated before the moment tl are ignored. The first trigger signal St generated after the moment t1 at the moments t2 ", t2" 'triggers the next suppression state. Therefore, when the trigger signal St has a repetition frequency higher than the highest frequency (60 KHz) within the prescribed frequency range, the first trigger signal St generated after a predetermined duration of the suppression period is It will trigger the next suppression cycle and the next control signal Sc. In this way the switching frequency of the first power source 1 occurs within the prescribed frequency range, equals to the repetition frequency of the trigger signal divided by an integer greater than 1, and not higher than the highest frequency within the prescribed frequency range, but possibly One high.

It is obvious that variations of the above-described embodiments may fall within the scope of the invention as claimed in the claims. This embodiment shows two synchronized power supplies 1 and 2, each synchronized by its own control signals SC1 and SC2, but according to one control signal having a repetition frequency in a suitable range of the two power supplies. The power supplies 1 and 2 may also be synchronized. It is also possible to synchronize only one power source. Instead of driving the water tube 4 with deflection current, the matrix display can be driven by row and column selection circuitry. The control circuit 6 may also be a microcomputer suitably programmed. The microcomputer detects the moment at which the trigger signal St is generated and generates the moment at which the control signal Sc is generated. The microcomputer may also perform the function of the synchronization circuit. The detected horizontal synchronization moment can be represented by several values. The moment at which the control signal Sc is generated is calculated based on the values. Instead of being synchronized to the trigger signal St, one of the power sources 1 and 2 may be synchronized to a signal or control signals Sc2 and Sc1 related to the other power source 2 and 1. In more detail, the control signal Sc1 of the first power source 1-becomes the main power source is configured to receive flyback pulses generated by the second power source 2 -EHT power source through the multivibrator 60. Can be obtained by distribution. Multivibrators 60 and 61 may be replaced by other circuitry that distributes frequency in a suitable manner.

It is an object of the present invention to switch a switching power supply synchronized to a line addressing frequency having a value within a large range of various line addressing frequency ranges without imposing a condition of the line addressing frequency.

In the first invention of the present invention, the repetition frequency of the control moment can exhibit a plurality of values within the frequency range as described above, and the step of determining the integer is within the prescribed frequency range by dividing the trigger repetition frequency by one integer. It is characterized in that the resulting integer is considered to be given the repetition frequency of the control moment.

The second invention of the present application is to provide a display system as defined in claim 5.

The third invention of the present application is to provide a control circuit as defined in claim 7.

A fourth invention of the present application is to provide an apparatus for synchronizing power to a line addressing repetition frequency of a line addressing circuit as defined in claim 8.

Advantageous embodiments of the invention are defined in the dependent claims of the claims.

The display system includes an image display apparatus, multiple scan rate line addressing circuits for scanning an image at different scan rates, and a switching power supply. The line addressing circuit causes a line scan of the positions on the image display device. These lines have a line addressing repetition frequency (referred to as line frequency) related to different scan rates. The line addressing circuit can be a line deflection circuit such as that used to scan conventional water tubes or a row / dot select circuit such as used in matrix displays. A trigger moment with a trigger repetition frequency equal to the line frequency is generated. The switching frequency of the power supply is determined by the control moment having a repetition frequency which is the repetition frequency of the trigger moment divided by an integer greater than zero. The constant is determined such that the repetition frequency of the control moment occurs within a defined frequency range. In this way, the power supply is synchronized to the trigger moment and operated at frequencies within the specified frequency range. The power supply is designed to operate without disturbances within the aforementioned displacement of the switching frequency.

When hardware circuitry is used to generate trigger and control moments, these moments can be coupled with moments whose level is changed by a signal. If the microcomputer generates a trigger and control moment, this may also be a signal that changes level as a value representing a predetermined moment.

In an embodiment of the method according to the invention, as characterized in claim 2, the integer is generated to be 1 if the line frequency is generated within a defined frequency range of the power supply switching frequency. The first advantage in this case is that the switching frequency of the power supply is equal to the line frequency so that switching of the components of the power supply occurs only once during each line period. If the switching frequency of the power supply is an integer multiple of the line frequency, this will cause distortion on the display device very frequently. This is a special case where the power source is used to generate the anode voltage of the receiver. The second advantage is that the line frequency is not divided by an integer greater than one when the line frequency still produces a switching frequency of the power supply which occurs within the defined frequency range.

As an example, if the specified frequency range includes frequencies from 15KHz to 60KHz and the line frequency is 45KHz, the power supply will switch at 45KHz and not at 30KHz or 15KHz. In this way, the power supply will operate as efficiently as possible and generate a stable output voltage as possible.

In an embodiment of the method according to the invention, as characterized in claim 3, the line frequency is higher than the highest frequency in the defined frequency range. An integer is generated to obtain the switching frequency of the power supply as high as possible occurring within the specified frequency range. This has the advantage that the power supply will operate as efficiently as possible and generate the output voltage as stable as possible.

Preferred embodiments according to the invention are characterized in claim 4. If the trigger moment is not generated during the preceding suppression period of the operating state, the trigger moment generates a suppression period with a predetermined duration and generates an associated control moment to switch the power supply. The predetermined duration corresponds to the highest frequency in the prescribed frequency range. If the trigger moment has a repetition frequency within the defined frequency range, all trigger moments will trigger a suppression period that will be inactive before the next trigger moment occurs. A control moment is generated for each trigger moment to obtain the switching frequency of the power source, which is equal to the line frequency. If the trigger moment has a repetition frequency that is higher than the highest frequency within the defined frequency range, the next suppression period and the next control moment until the first trigger moment occurs after a predetermined duration of the suppression period Triggering will continue. In this way the switching frequency of the power supply is generated within the specified frequency range and made as high as possible.

A preferred embodiment of a display system according to the invention is characterized in claim 6. The non-retractable multivibrator is triggered by a trigger signal to change to a disabled state with a predetermined duration. The trigger moment is a trigger signal and has no effect when the multivibrator is in the disabled state. The output of the multivibrator generates a signal indicating the disabled state. The control moment, which is the control signal, is either this output signal or related to this output signal. Again, the predetermined duration corresponds to the highest frequency in the defined frequency range. If the trigger signal has a repetition frequency within a defined frequency range, all trigger signals will trigger a suppression period that will be inactive before the next trigger signal is generated. A control signal is generated for every trigger signal. If the trigger signal has a repetition frequency higher than the highest frequency within the defined frequency range, triggering the next suppression period and the next control signal will continue until the first trigger signal occurs after a predetermined duration.

Reference signs in parentheses used in the claims should not be understood as limiting the scope of the claims.

Preferred embodiments for determining integers according to the present invention are summarized as follows.

The integer becomes 1 if the repetitive frequency of line addressing occurs within a prescribed frequency range of the power supply.

If the repetition frequency is higher than the highest frequency in the defined frequency range, the constant is determined so that the switching frequency of the power supply 1 and 2 occurs within the defined frequency range as close as possible to the highest frequency.

Claims (11)

Generating (in the addressing circuit 7) a trigger moment St having a trigger repetition frequency equal to the line addressing repetition frequency; Determining, in the decision control circuit 6, an integer greater than zero according to the trigger repetition frequency; Generates control moments Sc1 and Sc2 having a repetition frequency which is a trigger repetition frequency divided by the integer in response to the trigger moment St which determines the switching frequency of the power sources 1 and 2 (in the control circuit 6 A method of synchronizing the power supply 1, 2 to the line addressing repetition frequency of the line addressing circuit 7, the method comprising: The repetition frequency of the control moments Sc1, Sc2 may represent a plurality of values within a prescribed frequency range, The step of determining the constant (in the control circuit 6) divides the trigger repetition frequency by one integer to generate an integer that is considered to be provided with the repetition frequency of the control moments Sc1 and Sc2 within the prescribed frequency range. Characterized in that the power source (1, 2) synchronization method. 2. The power supply (1) according to claim 1, wherein the step of determining the constant (in the control circuit 6) is suitably changed such that the constant is equal to 1 for all trigger repetition frequencies within the prescribed frequency range. 2) Synchronization method. 3. The constant determination (in control circuit 6) step according to claim 2, wherein the step of determining the repetition frequency of the control signals Sc1 and Sc2 when the trigger repetition frequency is higher than the highest frequency within the prescribed frequency range. And is suitably modified to generate an integer having a value that is not higher than the highest frequency but as close as possible to the highest frequency within the prescribed frequency range. 4. The method of claim 3, wherein the integer determination (in the control circuit 6) step generates a suppression period having a predetermined duration in response to the trigger signal St (in the multivibrators 60, 61). Wow, Generating control signals Sc1 and Sc2 in response to the trigger signal St when the trigger signal St is not generated during the preceding function suppression period, wherein the predetermined duration Td is And a power source (1, 2) synchronization method according to the highest frequency. An image display device 4 for displaying image information Pi; A multi-scan speed line addressing circuit 7 for generating line addressing of the image display device 4 having a line addressing repetition frequency and generating a trigger signal St having a trigger repetition frequency equal to the line addressing repetition frequency; , A synchronized power source 1,2 for generating supply voltages Vb and Va, Means (6) for determining an integer greater than zero according to the trigger repetition frequency; Means for generating a control signal Sc1, Sc2 having a repetition frequency which is a signal for determining a switching frequency of the power sources 1, 2, that is, a trigger repetition frequency divided by the integer, in response to the trigger signal St. A display system comprising (6), The repetition frequency of the control signals Sc1 and Sc2 may represent a plurality of values within a prescribed frequency range, The constant determining means 6 is suitably modified to generate an integer which is considered to be provided with a repetition frequency of the control moments Sc1 and Sc2 within the prescribed frequency range by dividing the trigger repetition frequency by one integer. Display system, characterized in that. 6. The integer determining means (6) according to claim 5, characterized in that the integer determining means (6) has an input (B) coupled to receive the trigger signal (St) and an output (Q1, Q2) coupled to supply the control signals Sc1, Sc2. Non-triggerable multivibrator (60, 61) having a, When the trigger signal St is not generated during the preceding function suppression state, the multivibrator 60, 61 changes to a function suppression state having a predetermined duration Td due to the trigger signal St, And the output (Q1, Q2) remains in the disabled state when the trigger signal (St) occurs during the disabled state. Means (6) for determining an integer greater than zero according to the trigger repetition frequency, Means for generating a signal for determining the switching frequency of the power sources 1 and 2 in response to the trigger signal St, ie the control signals Sc1 and Sc2 having a repetition frequency which is a trigger repetition frequency divided by said integer (6) ), In the control circuit 6 for synchronizing the power supplies 1 and 2 to the trigger signal St having the trigger frequency equal to the line addressing repetition frequency of the line addressing circuit 7, The repetition frequency of the control signals Sc1 and Sc2 may represent a plurality of values within a prescribed frequency range, The constant determining means 6 is suitably modified to generate an integer which is considered to be provided with a repetition frequency of the control moments Sc1 and Sc2 within the prescribed frequency range by dividing the trigger repetition frequency by one integer. A control circuit (6) for synchronizing power sources (1, 2). Means for generating (in the addressing circuit 7) a trigger moment St having a trigger repetition frequency equal to the line addressing repetition frequency; Means for determining (in control circuit 6) an integer greater than zero in accordance with the trigger repetition frequency; Generates control moments Sc1 and Sc2 having a repetition frequency which is a trigger repetition frequency divided by the integer in response to the trigger moment St which determines the switching frequency of the power sources 1 and 2 (in the control circuit 6 And a means for synchronizing the power supply (1, 2) to the line addressing repetition frequency of the line addressing circuit (7). The repetition frequency of the control moments Sc1, Sc2 may represent a plurality of values within a prescribed frequency range, The constant determination (in control circuit 6) means divides the trigger repetition frequency by one integer to generate an integer that is considered to be provided with a repetition frequency of the control moments Sc1 and Sc2 within the prescribed frequency range. Apparatus for synchronizing power sources (1, 2). 9. The power supply (1) according to claim 8, wherein the means for determining the constant (in the control circuit 6) is suitably changed such that the constant is equal to 1 for every trigger repetition frequency within the prescribed frequency range. 2) Device for synchronization. 10. The repeating frequency of the control signals Sc1, Sc2 according to claim 9, wherein the means for determining the integer (in the control circuit 6) means that the trigger repetition frequency is higher than the highest frequency in the prescribed frequency range. Is adapted to generate an integer having a value that is not higher than the highest frequency but as close as possible to the highest frequency within the defined frequency range. 11. The method according to claim 10, wherein said constant determination (in control circuit 6) means generates a suppression period having a predetermined duration (in multivibrators 60, 61) in response to a trigger signal St, Means for generating control signals Scl and Sc2 in response to the trigger signal St when the trigger signal St is not generated during a preceding function suppression period, wherein the predetermined duration Td Apparatus for synchronizing power source (1,2), characterized in that corresponding to the highest frequency.

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