KR19990078503A - Combimeter system drive - Google Patents

Abstract

The present invention relates to a drive device of a combimeter (Speedo, Tacho, Odo) system used in automobiles. The present invention includes a microprocessor for receiving a speed signal and a taco signal, counting a frequency, calculating a rotation angle, and generating a pulse width modulated signal; A buffer / square wave converter for buffering a speed signal and a taco signal of a vehicle and shaping the square wave into a square wave and inputting the same to a frequency counter of the microprocessor, and a PWM / direct current converter for converting a PWM signal output from the microprocessor into a DC voltage. A phase shifter for changing a phase signal of the DC voltage signal input from the PWM / DC converter based on an offset adjustment signal, a DC voltage signal input from the PWM / DC converter and a phase change signal input from the phase shifter Driver unit for driving tachometer and speedometer by using, constant voltage source for supplying operation power to each component, various protection circuits, counting the mileage of the vehicle based on PWM signal input from the microprocessor and outputting it to the odometer PWM coefficient input from the distance coefficient driver and the microprocessor Based on the total running distance of the vehicle by counting the cumulative distance coefficient part is configured to output them to the driver IC odometer; And a meter unit including a tachometer, a speedometer, and an odometer to be driven by the control of the driver IC.

Description

Combimeter system drive

The present invention relates to a device for driving a combimeter (Speedo, Tacho, Odo) system used in automobiles.

Commonly used combimeters in automobiles can be divided into mechanical and cross-coil methods using several analog control ICs.

Mechanical is to display the speed proportional to the number of revolutions of the wheel by connecting wires from the vehicle's mission output, but this method is not only low accuracy, but also has a disadvantage of poor wear and noise compared to the electronic.

In addition, the cross-coil method using a plurality of analog control ICs uses a magnetic sensitive element to convert the output signal according to the rotation of the vehicle wheel into a sine and cosine voltage to drive the speedometer cross coil and the ignition coil according to the engine rotation speed. Alternatively, the pulse signal from the electronic ignition system is converted into a signed, cosine voltage to drive the tachometer cross coil. The distance integration meter divides the output signal according to the rotation of the vehicle wheel appropriately to drive the stepping motor to integrate the distance.

This method is currently applied to most vehicles except low-level vehicles, and operates at low frequencies below 0-200Hz in proportion to the signal generated inside the vehicle, that is, the engine speed (RPM) and driving speed (Speed). Since the effects of noise due to ripple cannot be ignored, the DC voltage conversion capability at low frequencies is poor. In addition, since the analog control IC is used, it is difficult to obtain the linearity of the DC voltage change with respect to the input frequency. Therefore, the meter controlled by the analog IC has low responsiveness and precision.

Therefore, the present invention was devised to improve the disadvantages of the cross-coil method using the analog control IC of the conventional combimeter, and the power noise and noise contained in the low frequency (Speed, RPM signal) input from the vehicle. It is an object of the present invention to provide a combimeter system driving device that has a stable characteristic with minimal impact.

Another object of the present invention is to realize a high accuracy by improving the linearity of the meter by the control of the microprocessor, as well as to improve the competitiveness of the product by reducing the cost, simplifying the assembly, and cost reduction It is to provide a drive of the system.

To achieve the above object, the driving apparatus of the combination system of the present invention comprises: a microprocessor which receives a speed signal and a taco signal, counts a frequency, calculates a rotation angle, and generates a pulse width modulated signal; A buffer / square wave converter for buffering a speed signal and a taco signal of a vehicle and shaping the square wave into a square wave and inputting the same to a frequency counter of the microprocessor, and a PWM / direct current converter for converting a PWM signal output from the microprocessor into a DC voltage. Power amplification circuit unit for driving the cross coil of the speed meter by shifting the phase and phase of DC voltage by 180 degrees according to the vehicle speed, and crossing the coil of the engine speed meter by shifting the phase and phase of DC voltage according to the engine speed by 180 degrees. A power amplifier circuit unit for driving, an error compensation circuit unit (offset adjustment unit) for compensating for errors of the coil wound around the cross coil, a power amplifier circuit unit for amplifying the power of the pulse signal output from the microprocessor to integrate the distance, and the tachometer of the meter unit Supplies 12V DC to the speedometer and supplies 5V to the microprocessor. A power supply unit, various protection circuits, a distance coefficient driver for counting the driving distance of the vehicle based on the PWM signal input from the microprocessor, and outputting the calculated distance to the odometer, and a total driving distance of the vehicle based on the PWM signal input from the microprocessor. A drive IC comprising an integration distance coefficient unit for counting and outputting the same to an odometer, and a meter unit including a tachometer, a speedometer, and an odometer to be driven by the control of the power amplification circuit unit of the drive IC.

The meter unit is driven by applying a reference voltage to the sign (+) and cosine (+) terminals of each air core, and applying a cosine signal to the sign (-) and cosine (-) terminals. It is done.

1 is an overall control block diagram of a combimeter system according to the present invention.

2 and 3 are detailed circuit diagrams of FIG. 1.

4 is an operational waveform diagram of the circuit diagram of FIGS. 2 and 3.

Explanation of symbols on the main parts of the drawings

10 ------ Microprocessor 20 ------ Driver IC

21 ------ Buffer / Square Wave Converter 22 ------ PWM / DC Converter

23 ------ Phase Shifter 24 ------ Meter Driver Section

25 ------ Constant voltage source 27 ------ Distance coefficient driver

28 ------ Accumulation distance coefficient driver

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is an overall control block diagram of a combination system according to the present invention, FIGS. 2 and 3 are detailed circuit diagrams of FIG. 1, and FIG. 4 is an operational waveform diagram of the circuit diagrams of FIGS. 2 and 3.

This system includes a microprocessor, a buffer for shaping input signals (Speed and Tacho signals), a protection circuit to remove various noises such as input signals, and a PWM signal output from the microprocessor in proportion to frequency. It consists of a DC voltage converter, a meter drive unit for outputting the converted voltage to a meter (Speedo, Tacho, Odo), and an analog bipolar IC composed of a power supply unit for supplying driving power to drive the microprocessor and all circuits. have.

In addition, the combimeter system of the present invention generates a frequency (0-200 Hz) in proportion to the frequency (0-10,000 Hz) and the running speed (Speed) of the engine RPM (RPM) as a signal generated inside the vehicle Using this frequency, the rotation angle is calculated, and has a control characteristic by a microprocessor to generate a PWM signal composed of a cosine curve, which is wrapped with the calculated operation value.

And, in the conventional analog control IC, the sine part and the cosine voltage are applied to both ends of the coil and the cosine curve coil, respectively, but in this system, the sign (+) and cosine (+) terminals at each cross-coil air core. The reference voltage is applied to the signal, and a cosine signal is applied to the sign (-) and cosine (-) terminals.

In more detail, as shown in FIG. 1, the combimeter system of the present invention includes a microprocessor 10, a drive IC 20, and a meter unit 30: Speedo, Tacho, and Odo.

Here, the microprocessor is 1) an 8-bit or 16-bit central processor unit (CPU) suitable for control applications, 2) has a wide range of bit logic processor capabilities, and 3) two 16-bit timers. / Counter, 4) 5 interrupts with double priority, 5) 12 byte data in RAM, 6) more than 14 input / output ports for direct input and output.

Therefore, by measuring the frequency accurately by the microprocessor 10, and calculates the cosine value, which is proportional to the value, and by driving the Air Core of the meter, the accuracy is improved compared to the conventional analog control IC driving.

In the combimeter system of FIG. 1, the drive IC 20 is an output stage IC for driving a meter unit 30 composed of a cosine air core, which converts a PWM signal output from the microprocessor 10 into an analog signal. .

The drive IC 20 buffers the speed signal and the taco signal of the vehicle, forms a square wave, and then inputs the buffer IC to the frequency counter of the microprocessor 10, from the microprocessor 10. A PWM / DC converter 22 for converting the output PWM signal into a DC voltage, an error compensating circuit part 55 (offset adjusting part) for compensating for the error of the coil wound around the cross coil, and the PWM / DC converter 22 A DC 12V is supplied to the driver unit 24 for driving the tachometer 31 and the speedometer 32, the tachometer 31 of the meter unit 30, and the speedometer 32 using the input phase change signal, and then a microprocessor. The power supply unit 25 for supplying the power 5V of the power source 10, various protection circuits 26, and counts the traveling distance of the vehicle based on the PWM signal input from the microprocessor 10 and outputs the same to the odometer 33. Distance coefficient driving unit (27) and Group consists of the accumulated odometer reservoir (28) for outputting to the microprocessor 10 by counting the total number of revolutions of the vehicle based on the PWM signal input from this misleading meter 33.

On the other hand, the PWM / DC converter 22, the phase shifter 23, the driver 24 is the first PWM / DC converter 22a, the first phase shifter 23a, so as to correspond to the tachometer 31, The tachometer driver 24a is configured, and the second PWM / DC converter 22b, the phase shifter 23b, and the speedometer driver 24b are configured to correspond to the speedometer 32, respectively.

Referring to the detailed circuit diagrams of FIGS. 2 and 3, the microprocessor 10 is configured with a crystal oscillator X-tal so as to count a frequency and a reset signal can be input.

In addition, the speed signal and taco signal are input to the buffer / square wave conversion unit 21 of the drive IC 20 through the resistor R3 and the resistor R4, respectively, and configured to be input to the microprocessor 10. It is.

In addition, the PWM signal output from the microprocessor 10, the signals passing through the transistors (Q1) (Q2) are respectively input to the operational amplifier (U1A) (U1B), the speed meter 32 to drive the cross-coil The signals, which are inputted to and passed through the transistors Q3 and Q4, are respectively input to the operational amplifiers U1C and U1D and then to the tachometer 31 to drive the cross coils. The operational amplifier (U1A) (U1C) is an output buffer of the power amplifier circuit is configured such that the non-inverting terminals (+) of the buffer receives each converted DC voltage and supplies an output voltage proportional to the value. The amplifiers U1B and U1D are configured such that the non-inverting terminals receive a reference voltage, and the inverting terminals receive respective converted DC voltages and are compared with each other. In this case, the reference voltage supplied to the non-inverting terminal of the operational amplifier U1B may be varied by the variable resistor VR1, and the reference voltage supplied to the non-inverting terminal of the operational amplifier U1D is the variable resistor VR2. It is configured to be variable by.

On the other hand, the pulse signal output from the microprocessor 10 is configured to be input to the non-inverting terminal (+) of the operational amplifier (U2A) (U2B), respectively, and to be input to the odometer 33 through the output buffer.

The operational amplifier (U1A) (U1B) is a power amplifier circuit 52 for driving the cross coil of the speed meter by shifting the phase and phase of the DC voltage according to the vehicle speed by 180 degrees, the operational amplifier (U1C) (UID) is the engine The power amplifier circuit unit 51 and the operational amplifiers U2A and U2B which drive the cross coil of the engine speed meter by shifting the phase and phase of the DC voltage according to the speed by 180 degrees from the microprocessor 10 to integrate the distance. A power amplification circuit section 53 for amplifying the power of the output pulse signal is configured.

In addition, the constant voltage source 25 is composed of a zener diode ZD1, which is a constant voltage element, to supply a constant voltage of 12 V at all times to the driver IC and the meter.

As the drive IC includes various functions as described above, it is necessary to construct a reliable drive IC by using a sufficiently verified circuit and an appropriate drive in circuit design and configuration.

The meter unit is driven by applying a reference voltage to the sign (+) and cosine (+) terminals of each air core, and applying a cosine signal to the sign (-) and cosine (-) terminals.

Referring to the operation of the cross-coil drive device of the combination system of the present invention configured as described above is as follows.

First, as a signal generated from the vehicle, a frequency of 12V (0-200 Hz for driving speed and 0-10,000 Hz for engine speed) is generated in proportion to the engine speed and the running speed, respectively. This frequency is input to the buffer / square wave converter 21 of the drive IC 20 through the resistors R3 and R4, and after the waveform is shaped, it is input to the microprocessor 10. In other words, the input signal is a pulse signal generated inside the vehicle, and the frequency is proportional to the engine rotation speed and driving speed. To be processed.

At this time, when the pulse signal is input to the external interrupt terminal of the two channels, an external interrupt occurs at the falling edge of the input signal, and frequency can be measured by measuring the time between pulses using an internal timer.

In addition, the microprocessor 10 calculates the rotation angle of the instrument guide at the measured frequency in order to drive the meter composed of the cross coils, and obtains the correct duty ratio for implementing the PWM signal proportional to the obtained rotation angle.

The PWM output thus obtained is output using a timer interrupt built into the microprocessor 10.

The PWM signal output from the microprocessor 10, the PWM signal for driving the speedometer 32 is a transistor (Q1) (Q2), the PWM signal for driving the tachometer (31) is a transistor (Q3) (Q4) Are input to each. At this time, the transistors are turned on only when a high level PWM signal is output from the microprocessor 10, and the signal (voltage) output from the transistor Q1 is applied to the non-inverting terminal of the operational amplifier U1A, and then The output power proportional to the value is applied to the speed meter 32, and the signal output from the transistor Q2 is applied to the inverting terminal of the operational amplifier U1B, and then compared with the reference voltage set in the non-inverting terminal. The result is applied to the speedometer 32. In this case, the voltage applied to the non-inverting terminal of the operational amplifier U1B is changed by the variable resistor VR1 when the offset adjustment is necessary.

In addition, the signal output from the transistor Q3 is applied to the non-inverting terminal of the operational amplifier U1C, the output power in proportion to the value is applied to the tachometer 31, the signal output from the transistor Q4 is calculated It is applied to the inverting terminal of the amplifier U1D, compared with the reference voltage set at the non-inverting terminal, and the comparison result is applied to the tachometer 31. In this case, the voltage applied to the non-inverting terminal of the operational amplifier U1D is changed by the variable resistor VR2 when the offset adjustment is necessary.

In this way, the signals output from the operational amplifiers U1A and U1B are applied to the speedometer 32, and the signals output from the operational amplifiers U1C and U1D are applied to the tachometer 31, constituting these meters. The meter is driven by applying a DC voltage to the cross coil.

At this time, the meter is controlled by the voltage applied to each coil, and is driven at an angle proportional to the voltage changing according to the cosine curve, as shown in FIG.

As described above, according to the driving device of the combimeter system of the present invention, in the meter driven by the conventional analog control IC, the angle of the sign (+), the sign (-), the cosine (+), and the cosine (-) Unlike the method of applying analog signal to the air core, the reference voltage is applied to the sign (+) and cosine (+) terminals of each air core, and is wrapped on the sign (-) and cosine (-) terminals. By applying a cosine signal to drive the meter can simplify the component, there is an advantage to improve the accuracy of the meter.

Claims (2)

A microprocessor configured to receive a speed signal and a taco signal, count a frequency, calculate a rotation angle, and generate a pulse width modulated signal; A buffer / square wave converter for buffering a speed signal and a taco signal of a vehicle and shaping the square wave into a square wave and inputting the same to a frequency counter of the microprocessor, and a PWM / DC converter for converting a PWM signal output from the microprocessor into a DC voltage. Power amplification circuit unit for driving the cross coil of the speed meter by shifting the phase and phase of DC voltage by 180 degrees according to the vehicle speed, and crossing the coil of the engine speed meter by shifting the phase and phase of DC voltage according to the engine speed by 180 degrees. A power amplifier circuit unit for driving, an error compensation circuit unit (offset adjustment unit) for compensating for errors of the coil wound around the cross coil, a power amplifier circuit unit for amplifying the power of the pulse signal output from the microprocessor to integrate the distance, and the tachometer of the meter unit Supply 12V DC to Speedometer, 5V Power to Microprocessor A power supply unit, various protection circuits, a distance coefficient driver for counting the driving distance of the vehicle based on the PWM signal input from the microprocessor, and outputting the calculated distance to the odometer, and a total driving distance of the vehicle based on the PWM signal input from the microprocessor. A drive IC comprising an integration distance coefficient unit for counting and outputting the count to an odometer; And Combimeter system driving apparatus comprising a meter unit consisting of a tachometer, a speedometer, an odometer to be driven by the control of the power amplifier circuit of the drive IC. The method of claim 1, wherein the meter unit applies a reference voltage to the sign (+) and cosine (+) terminals of each air core, and the cosine signal wrapped around the sign (-) and cosine (-) terminals. Combimeter drive system, characterized in that driven by applying.