REFERENCE VOLTAGE MONITORING DEVICE OF A/D CONVERTER AND COMPRESSOR MOTOR CONTROL DEVICE

• Main Author: HORI RYOSUKE
• Format: Patent
• Language: English; Japanese
• Published: 16.11.2017
• Subjects: BASIC ELECTRONIC CIRCUITRY; CODE CONVERSION IN GENERAL; CODING; DECODING; ELECTRICITY

PROBLEM TO BE SOLVED: To monitor an accurate reference voltage to which a fluctuation is reflected even when the reference voltage for A/D conversion supplied to a circuit incorporating an A/D converter varies due to disturbance such as noise on a supply path to the circuit.SOLUTION: A grounding port of a microcomputer 17 to which a grounding capacitor C of an internal power supply 17b is connected is connected to an analog input port P2, an operation power supply voltage Vdd generated by the internal power supply 17b is input to the analog input port P2, and subjected to a digital conversion by the A/D converter 17a of the microcomputer 17. The value (digital value) of the operation power supply voltage Vdd after the digital conversion is compared with the value of the operation power supply voltage Vdd which is known, and, for example, if the digital value of the operation power supply voltage Vdd by the A/D converter 17a is higher, it is recognized that a reference voltage Vref has decreased from the normal value.SELECTED DRAWING: Figure 6 【課題】Ａ／Ｄ変換部を内蔵する回路に供給されるＡ／Ｄ変換用の基準電圧が回路に対する供給経路上でノイズ等の外乱の影響を受けて変動しても、その変動が反映された正しい基準電圧を監視する。【解決手段】内部電源１７ｂの接地コンデンサＣが接続されるマイコン１７の接地ポートをアナログ入力ポートＰ２に接続し、内部電源１７ｂが生成した動作用電源電圧Ｖｄｄをアナログ入力ポートＰ２に入力して、マイコン１７のＡ／Ｄ変換部１７ａでデジタル変換させる。デジタル変換後の動作用電源電圧Ｖｄｄの値（デジタル値）を、既知である動作用電源電圧Ｖｄｄの値と比較し、例えば、Ａ／Ｄ変換部１７ａによる動作用電源電圧Ｖｄｄのデジタル値の方が高ければ、基準電圧Ｖｒｅｆが正常値から低下したと認識する。【選択図】図６