| 摘要 |
PURPOSE: An electronic control unit is provided to protect a circuit by cutting off reverse voltage and surge voltage and to realize accurate data communication by blocking up noises and adding a circuit having an accurate hysterisis. CONSTITUTION: An electronic control unit comprises a first resistor(R1) for restraining an input terminal in a high state when a detecting device is not connected with the data input terminal, third diode(D3) and third and fourth capacitors(C3,C4) for preventing breakage of a circuit by filtering reverse voltage and serge voltage due to short of a power source, a first variable resistor(VR1) for cutting off high voltage surge applied to the data input terminal by connecting first and second diodes(D1,D2) with VI, and a first capacitor(C1) connected with a case ground for removal of external noise. Herein, output voltage of a voltage dividing circuit is restrained from flowing to an input power terminal. By using VI as supply voltage for a hysterisis circuit, hysterisis voltage interlocking to a battery voltage(VB) is determined. Thus, the maximum hysterisis depending on the level of an input signal interlocking to the battery voltage is obtained. Therefore, accurate reception of noise and input signals is possible.
|
