JPH0443425B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improvement in a trimming circuit for compensating for variations in characteristics of electronic components.

[Technical background of the invention and its problems]

Electronic components such as resistors and transistors generally have variations in their values and characteristics, so if they are used as is, they may not be expected to operate according to specifications. For this reason, conventionally, a trimming circuit is generally provided in the electronic circuit to compensate for the above-mentioned variations. FIG. 6 shows an example of the configuration of a radio device equipped with a conventional trimming circuit.
In the same figure, a signal output from a microphone 61 is amplified by an amplifier 62 and then sent to a transmitting circuit 6.
3, and then amplified by a power amplifier 64 and then transmitted from an antenna 66 to a radio line via a duplexer 65. On the other hand, the received signal arriving via the wireless line is transmitted to the antenna 66 and the duplexer 65.
The signal is then received by a receiving circuit 67, then amplified by an amplifier 68, and output as an audible sound from a speaker 69. Here, the transmitting circuit 63 and the receiving circuit 67 are controlled by a control circuit 70, and the channel designation is made by a synthesizer 71. Incidentally, reference numeral 73 stores registration number information unique to the radio, and this registration number information is read out and transmitted when necessary by the control circuit 70 in order to prevent unauthorized use of the radio.

By the way, the trimming circuit 80 includes a regulator 81 made of a semi-fixed variable resistor and a terminal 82 for detecting the output signal level thereof, and is inserted between the amplifier 62 and the transmitting circuit 63. When trimming is performed using this trimming circuit 80, a measuring device is connected to the detection terminal 82, and the operator visually checks the display value of the measuring device to adjust the output signal level to a predetermined value. adjuster 81
are adjusted manually.

For this reason, it takes several seconds to several tens of seconds to perform trimming work at one location, and adjustment efficiency and accuracy are significantly reduced because adjustments vary depending on the operator and adjustment errors are likely to occur. It was.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a trimming circuit that can perform trimming work uniformly and accurately regardless of the operator in a short time, thereby greatly improving adjustment efficiency and accuracy.

[Summary of the invention]

In order to achieve the above object, the present invention includes a level detection circuit that inserts a level variable circuit in a signal path that outputs a signal according to the level of an external control signal, and detects the output signal level of this level variable circuit. , a trimming control means and a non-volatile memory are provided, and the trimming control means compares the output signal level detected by the level detection circuit at the time of trimming with a preset reference level, and based on the comparison result, both levels are adjusted. A trimming control signal for equalizing the levels is generated and supplied to the level variable circuit, thereby varying the signal level of the signal path, and the signal level detected by the level detection circuit and the reference level are The trimming control signal when they become equal is stored in a nonvolatile memory.

[Embodiments of the invention]

FIG. 1 shows the configuration of a trimming circuit according to an embodiment of the present invention. In the figure, the circuit portions of the radio device are designated by the same reference numerals as in FIG. 6, and detailed explanation thereof will be omitted.

A level variable circuit 11 is inserted between the transmitting signal amplifier 62 and the transmitting circuit 63, and a detection terminal 13 for detecting the output signal is derived from the output terminal of the level variable circuit 11. has been done. The level variable circuit 11 adjusts the level by varying, for example, the resistance value between the drain and source of the FET using the control voltage value of the gate. It is supplied via a vessel 12.

Now, this control circuit 20 is a microprocessor.
A ROM that includes a CPU 21 and stores a control program for the CPU 21 in the CPU 21 via a bus 22.
23, and a backup power supply 2 that stores control information.
4a and an input/output circuit (I/O) 25 that outputs trimming control information to the D/A converter 12, and inputs and outputs signals to a mode constant switch 28 and a display 29. Input/output circuit (I/O) 26 and measuring instrument 1
Input/output circuits (I/O) 27 for inputting detection data of No. 4 are connected to each other.
Further, a memory 73a for storing registration number information is connected to the bus 22. The registration number storage memory 73a is composed of, for example, an E ² PROM which is an electrically writable PROM, and is used to store trimming control signals, which will be described later. Erasure prevention means is provided only in the registration number information storage area to ensure that the information is never erased or changed.

Incidentally, the CPU 21 has, in addition to the function of controlling various operations related to transmission and reception, a trimming control means 21a and a trimming control information storage control means 21b as shown in FIG.
The trimming control means 21a performs trimming control according to a predetermined procedure based on the detection data of the measuring device 14 when the trimming mode is specified by the mode specifying switch 28. Further, when the transfer mode is designated by the mode designation switch 28 after trimming, the trimming control information storage control means 21b transfers the trimming control information temporarily stored in the RAM 24 in the control circuit 20 to the registration number information storage memory. 73a to a predetermined vacant address.

Next, the operation of the circuit configured as above will be explained according to the trimming adjustment procedure. During standby, the CPU 21 of the control circuit determines whether the mode is transmitting/receiving mode (step 3a), trimming mode (step 3b), or trimming control information transfer mode based on the switching state of the mode designation switch 28 as shown in FIG. It is determined whether there is one (step 3c).

Now, in order to carry out trimming, the operator connects the measuring device 14 to the detection terminal 13 and connects the detected data output terminal to the control circuit 20, and in this state switches the mode designation switch 28 to the trimming mode. becomes the trimming control mode shown in FIG. That is, first step 4a
In step 4b, the detection data digitized by the A/D converter is input from the measuring device 14, and in step 4b, this detection data is compared with a reference value stored in the ROM 23 in advance. Then, in step 4c, the value of the trimming control information is set according to the comparison result so that the detected data is equal to the reference value, and the set trimming control information is output to the D/A converter 12 in step 4d. . Then, the trimming control information is converted into an analog value and supplied to the control terminal of the level variable circuit 11, and as a result, the line resistance value changes and the output signal level is variably controlled. The variable output signal level is detected by the measuring device 14 and fed back to the control circuit 20. Then, in step 4e, the CPU 21 inputs the detection data of the measuring device 14, and in step 4f determines whether or not this detection data is equal to the reference value. If they are not equal, the control from step 4a to step 4f is repeated until they become equal, and when it is determined that they are equal, the process proceeds to step 4g, where trimming is performed when the detected data and the reference value are equal. The control information is stored in the RAM 24, and in step 4h, a trimming completion signal is output to the display 29 to notify the operator that trimming has been completed. In this way, the transmitted signal is trimmed.

On the other hand, when the mode designation switch 28 is switched to the trimming control information transfer mode after this trimming is completed, the CPU 21 detects this designation in step 3c of FIG. 3 and sets the control mode to the trimming control information transfer mode shown in FIG. do. That is, first, in step 5a, trimming control information is read from the RAM 24, and this trimming control information is stored in the registration number information storage memory 73 in step 5b.
Transfer it to a vacant address a and store it. Then, in step 5c, a determination is made as to whether or not the storage is complete. If the storage is completed, the process moves to step 5d, where the display 2
A transfer end signal is output to 9 to notify the operator that the transfer has been completed. The series of trimming operations is thus completed.

Therefore, if you operate the mode designation switch 28 to set the transmit/receive mode after completing this trimming, the CPU 2 will be activated every time you turn on the radio.
1, trimming control information is read out from the registration number storage memory 73a, and this trimming control information is sent to the level variable circuit 1 via the D/A converter 12.
1, thereby trimming the transmitter circuit.

As described above, in this embodiment, by providing the trimming control means in the control circuit of the radio,
The operator only needs to connect the measuring device 14 to the detection terminal 13 and its data output terminal to the control circuit 20, and the rest is automatically trimmed by the CPU 21, so trimming adjustment is independent of the operator. This can be done in a short time and with high precision, thereby shortening the adjustment time and improving the adjustment accuracy. This is more effective as the number of trimming points increases. Moreover, in this embodiment, the control circuit is provided with a trimming control information transfer control means, and this transfers the trimming control information to the registration number information storage memory 73a and stores it therein, so that the storage area of the RAM 24 can be trimmed. The control information makes it possible to effectively use it for transmission and reception control without occupying it. Here, the registration number information stored in the registration number information storage memory 73a is usually 4 to 5 bytes, and the memory capacity in the case of E ² PROM is as small as 32 bytes. Therefore, there is a free space in the memory that is not normally used, and storing trimming control information in this free space as in this embodiment makes effective use of the existing memory, and as a result, new Since there is no need to provide a memory, this is extremely effective in simplifying the circuit configuration and making it smaller.

Note that the present invention is not limited to the above embodiments. For example, if there is sufficient room in the RAM, the trimming control information may be stored in the RAM as it is without being transferred to the registration number information storage memory. Further, in the above embodiment, the case where trimming is performed on the transmitting circuit system has been described, but the trimming may be performed on the receiving circuit system or other parts, and the trimming location and number are not limited. In addition, the structure of the level variable circuit, the level detection circuit, the nonvolatile memory for storing trimming control information, the structure of the trimming control means,
The control procedure, control contents, configuration of the trimming control information transfer control means, etc. can be modified in various ways without departing from the gist of the present invention.

〔Effect of the invention〕

As described in detail above, according to the present invention, a level variable circuit that outputs a signal according to an external control signal level is inserted in a signal path, and a level detection circuit that detects the output signal level of this level variable circuit. , a trimming control means and a non-volatile memory are provided, and the trimming control means compares the output signal level detected by the level detection circuit at the time of trimming with a preset reference level, and based on the comparison result, both levels are adjusted. A trimming control signal for equalizing the levels is generated and supplied to the level variable circuit, thereby varying the signal level of the signal path, and the signal level detected by the level detection circuit and the reference level are By storing the trimming control signal when they become equal in nonvolatile memory,
It is possible to provide a trimming circuit that can perform trimming work uniformly and accurately in a short time and regardless of the operator, thereby greatly improving adjustment efficiency and accuracy.

[Brief explanation of drawings]

1 to 5 are for explaining a trimming circuit according to an embodiment of the present invention. FIG. 1 is a circuit configuration diagram of the same circuit, and FIG. 2 is a diagram of a control circuit.
A block diagram showing the functional configuration of the CPU, FIGS. 3 to 5 are flowcharts showing the control procedure and contents of the CPU, and FIG. 6 is a circuit configuration diagram of a radio device equipped with a conventional trimming circuit. 11... Level variable circuit, 12... D/A converter, 13... Output signal level detection terminal (detection terminal), 14... Measuring instrument, 20... Control circuit, 21
...CPU, 21a...Trimming control means, 2
1b...trimming control information transfer control means, 22
...Bus, 23...ROM, 24...RAM, 2
4a... Backup power supply, 25, 26, 27...
...Input/output circuit (I/O), 28...Mode designation switch, 29...Display device.

Claims (1)

[Claims] 1. A level variable circuit inserted in a signal path and outputting a signal according to an external control signal level; a level detection circuit detecting the output signal level of this level variable circuit; Trimming control means that compares the output signal level detected by the level detection circuit with a preset reference level, generates a trimming control signal for making both levels equal based on the comparison result, and supplies the signal to the level variable circuit. and a nonvolatile memory that stores and holds the trimming control signal when the signal level detected by the level detection circuit and the reference level become equal. 2 Non-volatile memory is a type of memory that can be electrically written to store individual information set for each electronic device.
The trimming circuit according to claim 1, which comprises a ROM.