JPS62213569A - Phase controlling device - Google Patents

Abstract

PURPOSE:To control a phase in high accuracy with a simple circuit by containing a counter, registers and an A/D converter in a microcomputer. CONSTITUTION:An A/D converter 16, a timer 21, an input/output port 22, and an internal bus 22 are provided in a control microcomputer. The timer 21 has a zero-cross counter 17, registers 18, 20, and an overflow counter 19. The counter 17 starts to automatically set a trigger OFF time to a switching element by the register 18 at every zero-cross signal of an input voltage. The counter 19 starts to automatically set a trigger ON time by the register 20 when the counter 17 overflows to turn OFF the trigger ON signal at overflowing time. The converter 16 is automatically started by the zero-cross signal input.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a phase control device using a microcomputer.

[Conventional technology]

For example, the Rogen lamp, which is widely used as a light source for exposure in conventional electrophotographic copying machines, etc.
Since the amount of light changes in proportion to the 3.8th power of the voltage due to fluctuations in the external input voltage, phase control is performed to keep the amount of light substantially constant. To do this, two counters are required: one to measure the off-duty in duty ratio control, and the other to create a trigger to turn on the triac (bidirectional three-terminal thyristor) as a switching element. 0 If the above device is configured using a CPU,
First, in the case of a CPU that does not have multiple built-in counters,
As shown in FIG. 4, a conventional example of a lamp exposure device using an external counter and an OPU, the counters 11, 12
requires external connection, and 16 input/output ports are required to set the set values for each of these counters.In addition, 8 ports for input from the analog-to-digital (A/D) converter 5 are required. In addition, in the figure, l is for the light source, 2 is a transformer, 3 is a rectifier bridge, and 4 is a rectifier bridge. Effective value detection circuit - 6 is a comparator, 7 is its reference voltage source, 8 is a zero cross generation circuit, 9 is a triac, 10 is a photocoupler and a protection circuit.
．． 12 is an 8-bit counter, and +3 is a CPU.

As mentioned above, the CPU 13 requires a large number of input/output boards, and one CPU is required only for this control, and it also becomes complicated in terms of a single domain, so there is no advantage to it. [Problem to be solved by the invention] In order to compensate for the above-mentioned drawbacks, for example, as shown in FIG. ) Even if an exposure device is configured using an existing O)'Ul 4 with a built-in counter, in order to set the set value for each built-in counter, it is necessary to first store the set value in a register and then input into the first counter, and
After setting the next setting value in the register, it had to be input into the second counter. Furthermore, these series of operations can only be performed using an interrupt (interrupted), such as an interrupt when the counter overflows, or an interrupt when the counter overflows.
Including the interrupts from the /D converter 5, etc., requires a large number of interrupts, making the program complex and making high-speed control difficult.

The present invention has been made in view of the above-mentioned problems of the prior art, and aims to provide a phase control circuit that can eliminate the above-mentioned drawbacks and control the exposure amount of a lamp, for example, as described above, with a simple circuit. The purpose is

[Means for solving problems]

Therefore, in the present invention, a second register and a first register are provided for controlling the trigger time for controlling the on/off duty of the switching element for each zero-crossing signal of the input voltage.
a second register and a second counter for controlling the trigger time by the operation of the counter, and an analog-to-digital converter that is started every time the zero-crossing signal is input; [Operation] The above-described CPU configuration simplifies the phase control circuit and contributes to increasing the efficiency of the proger inter even in terms of software. Embodiments] The present invention will be described below based on Examples. shows a block diagram of a part of the OPU.

(Configuration and Operation) The feature of this embodiment is that the first/second counter l7/+9 and the A/D converter 16 are replaced with the conventional control micro combinator in the CPU 15. In the figure, 21 is a timer section, 22
indicates an input/output port block, and 23 indicates an internal bus.

In FIG. 1, the same (equivalent) components as in FIGS. 4 and 5 of the prior art example described above are indicated by the same reference numerals, but will be explained in a supplementary manner. 1 is an exposure lamp C710 Gen lamp for copying machines, etc.
2Fi, the secondary side voltage of the o-trough 120, which is a transformer for detecting the voltage applied to the lamp 1, is full-wave rectified by the rectifier bridge 3, and converted to an effective value by the effective value detection circuit 4. Built-in broken in 0PUI5-p A/
At 0 input to the D converter 16 (FIG. 2), the digitized signal is processed in the CPU 15, and is stored in the zero cross counter 17 setting register 18 and the overflow counter 19 setting register 20. Next on
This process is performed while the zero cross counter 17 is counting up.The signal full-wave rectified by the rectifying element bridge 3 is output to (plus) terminal, and is compared with the reference voltage generated by the reference voltage source 7. If the ten input of the comparator 6 approaches Ov, the Therefore, Ov is set by the reference voltage source 7.
), the output becomes a low level, and a zero-crossing detection signal is sent from the zero-crossing signal generating circuit 8 to the CPU 15. CPU15 that received the zero cross signal
After setting a new set value in the zero-cross counter 11 using the register 18, the zero-cross counter 11 is started and the internal clock starts counting up. The triac 9 as a switching element remains off until the zero cross counter 11 overflows.

Next, when the zero cross counter 11 overflows, the over 70 counter 19 is loaded from the register 20, the over 70 counter 19 is automatically started, and the trigger signal of the triac 9 is sent to the photocoupler 10. Turn on. At this time, the zero cross counter 17i is stopped. Then, when the overflow counter 19 finishes counting for the on-duty time, it turns off the trigger signal of the triac 9 to the photocoupler IO.

Through the series of operations described above, the light amount of the lamp 1 is controlled to be constant. In this case, the two counters 17. ! 9 operates independently of the processing of the CPU 15, so the CPU 15 can perform setting value calculations and other functions, so that the control speed is not hindered.

(Flow of Interruption) FIG. 3 shows a flowchart of the A/D conversion end interrupt of this embodiment. The A/D converter 16 (FIG. 2) inside the CPU 15 samples and converts the effective value only once using the zero-cross pulse outputted from the zero-cross signal generating circuit 8 (FIG. 1). Then, when the A/D conversion is completed, an interrupt is generated internally. In this, the third
As shown in the figure, in step S-1, the sampled effective value is compared with a reference value that determines the amount of light, and the width of the on-off duty is determined so as to always match the reference value, and each setting register 18. Set the set value in 20 (S-2).If you change the reference value according to the density of the original using a routine other than the interrupt routine (S-3), each time, It becomes possible to obtain a constant amount of light that matches the density of the original (S-4, S
-5) 0 Since the processing performed in this interrupt routine only needs to be completed before the zero cross counter 11 overflows, this interrupt routine stores the A/D conversion data in some register. You may also have them do only that.

(Other Application Examples) By using the OPU according to the present invention as described above, it is possible to not only control the copying machine exposure/pull light amount of this embodiment, but also
It can also be applied to temperature control using highly accurate phase control, motor phase control, etc.

〔Effect of the invention〕

As described above based on the embodiments, by using the CPU configured according to the present invention, the configuration of the phase control device can be simplified and the efficiency of the progeratung can be improved.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of an embodiment of a lamp exposure apparatus according to the present invention, FIG. 2 is a block diagram of a part of its CPU, FIG. 3 is an interrupt flowchart in FIG. 2, and FIGS. 4 and 5. are two examples of circuits of a conventional lamp exposure apparatus. l...Lamp 9...Triac (switching element) IO...Photocoupler 15... ...CPU (microcomputer) 16...A/D converter 17/19...Zero cross/over 70
-Cow/Ri (1st/2nd) +8/20・・・・・・Register (1st/2nd)
21... Timer section C, PL/Program diagram of old inner enclosure (- enclosure) Figure 2 201:1. Scattered interruption flowchart No. 3
figure

Claims (1)

[Claims] In a phase control device using a microcomputer,
A first counter that automatically sets and starts the trigger off time for the switching element using a first register for each zero-crossing signal of the input voltage, and a second register that automatically sets the trigger on time for the switching element when the counter overflows. The microcomputer is characterized by having a built-in second counter that is set and started and turns off the trigger-on signal when the trigger-on signal overflows, and an analog-to-digital converter that is automatically started when the zero-crossing signal is input. phase control device.