KR20150045630A - Circuit for calibrating automatically output value of battery charge voltage - Google Patents

Abstract

The present invention relates to a circuit for automatically calibrating an output value of a battery charging voltage which reads the output voltage value of a battery charger by changing battery voltage at stages by using an analog to digital converter (DAC) and reads high-precision charging voltage over 0.01V by applying a linear interpolation method to the output voltage value.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a battery charging voltage output value automatic calibration circuit,

[0001] The present invention relates to an automatic output voltage calibration circuit for a battery charging voltage, and more particularly, to a voltage calibration circuit for reading an output voltage value of a battery charger while changing a battery voltage to a predetermined value using a digital analog converter (DAC) To an output value automatic calibration circuit of a battery charge voltage capable of reading a high-accuracy charge voltage of 0.01 V or more.

Generally, the battery voltage reading circuit uses a battery voltage divider, an RC filter, and the like.

That is, conventionally, a voltage compensation method using a simple voltage divider without considering the attenuation characteristic of the RC filter is used, or a method of manually adjusting the voltage is used.

However, since the error of the charge termination voltage becomes smaller as the accuracy of the reading of the battery charging voltage becomes higher, the accuracy of 0.01 V is required. However, the resistance R and the capacitor (C) elements having a 1% Even though the characteristics of the voltage are different for each board depending on the temperature, the precision of the components, the characteristics of the filter, and the state of the PCB, an error occurs.

In particular, in the case of a multi-charger in the form of a direct and parallel hybrid type of electric vehicle battery, the accumulation of such errors has a serious adverse effect on the lifetime and the use time of the battery due to the voltage unbalance.

In other words, conventionally, even if a resistor (R) and a capacitor (C) having a time constant of 1% class are used, an error to read the voltage of all the PCBs at the time of manufacturing is extremely large. There is a problem that it is necessary to adjust it again according to the change of the ambient temperature.

Also, when reading the battery voltage, battery current, and battery temperature, the battery voltage becomes non-linear due to the different characteristics of each PCB even if the high-precision F-class parts with expensive R, L and C circuits are used. There is a problem to change parameters.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a battery charger that reads an output voltage value of a battery charger while changing a battery voltage step by step using a digital analog converter (DAC) And an output value automatic calibration circuit of a battery charge voltage capable of reading a high-precision charge voltage as described above.

These and other objects of the present invention will be apparent to those skilled in the art without departing from the scope of the present invention by the appended claims.

According to another aspect of the present invention, there is provided an automatic output value correction circuit for a battery charging voltage, comprising a first FET Q1 and a second FET Q3 connected in parallel to one end of a battery BT1, A first resistor R37 and a second resistor R43 are provided on the input side of the FET Q1 and the second FET Q3 to adjust the amounts of the currents flowing through the first and second FETs to the same value, A DA converter U29 is connected to the output sides of the first FET Q1 and the second FET Q3 and a third resistor R31 is connected to the output side of the contact point where the first and second FETs and the DA converter meet, A fourth resistor R75 and a diode D6 are connected to ground at the other end of the third resistor R74 and a zener diode D13 and a diode D11 are connected to each other, The grounded elements are connected in parallel to output an output signal to the output terminal ChO, and the other end of the battery BT1 is connected to the third FET A fifth resistor R54 for preventing overcurrent is connected to the input side of the third FET Q5 and a sixth resistor R77 and a diode D12 are connected to the output side of the third FET Q5 And the Zener diode D14 and the diode D15 are connected to each other so that the grounded elements are connected in parallel to output the output signal to the output terminal Ch1.

According to an automatic output voltage correction circuit for a battery charging voltage according to the present invention, an output voltage value of a battery charger is read while a battery voltage is gradually changed using a digital analog converter (DAC), and linear interpolation is applied to the output voltage value A high-precision charge voltage of 0.01 V or more can be read.

Additional features and advantages of the present invention will become more apparent from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a circuit diagram showing an output value automatic calibration circuit of a battery charging voltage according to the present invention. FIG.
Fig. 2 shows a nonlinear graph applied to the present invention. Fig.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a battery charging voltage output value automatic calibration circuit according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

In the present specification, the following embodiments and embodiments are to be considered as illustrative and not restrictive, and the invention is not to be limited to the details given herein but is to be accorded the scope of the appended claims and their equivalents, Can be changed to an example.

FIG. 1 is a diagram showing an output value automatic calibration circuit of a battery charging voltage according to the present invention, and FIG. 2 is a diagram showing a nonlinear graph applied to the present invention.

First, an internal digital / analog converter (DA converter) having a 12-bit resolution with a 0 to 5V output is built in the voltage readout circuit portion of the battery, and the DA voltage through the DA converter is stepped up to a voltage of 0 to 5V And converting the AD conversion table data into a table data. The AD conversion table data is represented by a non-linear graph reflected in the RC filter attenuation characteristic, the temperature characteristic of the component, and the surrounding environment, and the linear interpolation The charging voltage of the battery can be read with a high accuracy of 0.1 V or more.

That is, as shown in FIG. 1, the output voltage auto-correcting circuit of the present invention includes a first FET Q1 and a second FET Q3 connected in parallel to one end of a battery BT1, A first resistor (R37) and a second resistor (Q3) are provided on the input side of the first FET (Q1) and the second FET (Q3) for controlling the amounts of currents flowing through the first and second FETs to the same value, A DA converter U29 is connected to the output sides of the first FET Q1 and the second FET Q3 and an output terminal of the DA converter is connected to the output side of the contacts where the first and second FETs and the DA converter meet, A fourth resistor R75 and a diode D6 are connected to the other end of the third resistor R74 and grounded. A zener diode D13 and a diode D11 are connected to one end of the third resistor R74. And the grounded elements are connected in parallel to output the output signal to the output terminal ChO.

The third FET Q5 is connected to the other end of the battery BT1 and the fifth resistor R54 for preventing overcurrent is connected to the input side of the third FET Q5. The sixth resistor R77 and the diode D12 are connected to ground and the zener diode D14 and the diode D15 are connected so that the grounded elements are connected in parallel to output the output signal to the output terminal Ch1 do.

Therefore, as shown in FIG. 2, it is possible to read a high-precision battery charging voltage of 0.01 V or more by using linear interpolation on the graph of the output voltage value of the battery charger, wherein the output value Y = (y2-y1) / (x2-x1) x.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, Of course.

Claims (1)

A circuit for automatically calibrating an output value of a battery charging voltage,
The first FET Q1 and the second FET Q3 are connected in parallel to one end of the battery BT1 and the first FET Q1 and the second FET Q3 are connected to the first FET Q1 and the second FET Q3, The first resistor R37 and the second resistor R43 are connected to each other to control the amount of current flowing through the first FET Q1 and the second FET Q3 to the same value, One end of the third resistor R74 is connected to the output side of the contact point where the first and second FETs and the DA converter meet, and the other end of the third resistor R74 is connected to the fourth end of the fourth resistor R74. The resistor R75 and the diode D6 are connected to ground and the zener diode D13 and the diode D11 are connected to grounded elements to output the output signal to the output terminal ChO,
A third FET Q5 is connected to the other end of the battery BT1 and a fifth resistor R54 for preventing overcurrent is connected to the input side of the third FET Q5. The sixth resistor R77 and the diode D12 are connected and grounded and the zener diode D14 and the diode D15 are connected to grounded elements in parallel to output an output signal to the output Ch1 Features a battery charging voltage output value auto-calibration circuit.

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