Ground detecting apparatus and relay action detecting apparatus

Patent metadata

Field	Value
Publication number	US-9853440-B2
Application number	US-201514819993-A
Country	US
Kind code	B2
Filing date	Aug 6, 2015
Priority date	Oct 9, 2014
Publication date	Dec 26, 2017
Grant date	Dec 26, 2017

Abstract

A ground detecting apparatus at least includes a metal oxide semiconductor field effect transistor and a high voltage resistor. The metal oxide semiconductor field effect transistor is used to replace a photo-coupler for switching. The high voltage resistor is used for safety isolation. A relay action detecting apparatus at least includes a metal oxide semiconductor field effect transistor and a high voltage resistor. The metal oxide semiconductor field effect transistor is used to replace a photo-coupler for switching. The high voltage resistor is used for safety isolation.

First claim

What is claimed is:

1. A ground detecting apparatus electrically connected to an alternating current power supply apparatus, the ground detecting apparatus comprising:
a diode unit electrically connected to the alternating current power supply apparatus and generating a direct current voltage;
a high voltage resistor comprising a first terminal and a second terminal, the first terminal of the high voltage resistor electrically connected to the diode unit, the second terminal of the high voltage resistor electrically connected to a first terminal of a first resistor, a second terminal of the first resistor electrically connected to a ground terminal;
a metal oxide semiconductor field effect transistor comprising a drain, a gate and a source, the gate electrically connected to the high voltage resistor and the first resistor, the source electrically connected to the ground terminal; and
a controller electrically connected to the drain,
wherein the direct current voltage is divided by the high voltage resistor and the first resistor to obtain a judgment voltage to send to the gate; an on-off state of the metal oxide semiconductor field effect transistor is determined with the judgment voltage, and then a voltage level of the drain is changed to generate a pulse voltage signal; the controller performs detection according to the pulse voltage signal.

2. The ground detecting apparatus in claim 1 , wherein a plurality of resistors in series forms the high voltage resistor; the alternating current power supply apparatus and the metal oxide semiconductor field effect transistor are complied with a safety regulation of high voltage isolation according to a withstanding voltage of each of the resistors.

3. The ground detecting apparatus in claim 1 , wherein the controller compares the pulse voltage signal with a predetermined value to determine a ground state.

4. The ground detecting apparatus in claim 3 , wherein the predetermined value is a time value or a frequency value.

5. The ground detecting apparatus in claim 1 , wherein the diode unit comprises a first diode and a second diode electrically connected to two power lines of the alternating current power supply apparatus respectively to generate the direct current voltage with rectification.

6. The ground detecting apparatus in claim 5 , further comprising a zener diode electrically connected to the metal oxide semiconductor field effect transistor, the zener diode clamping the judgment voltage to protect the metal oxide semiconductor field effect transistor to prevent the gate from excessive voltage.

7. The ground detecting apparatus in claim 6 , further comprising a driving voltage supply unit and a current limiting resistor, the driving voltage supply unit and the current limiting resistor arranged in series and electrically connected to the metal oxide semiconductor field effect transistor, the driving voltage supply unit providing the voltage level.

8. The ground detecting apparatus in claim 7 , further comprising a second resistor and a capacitor, the second resistor and the capacitor connected in parallel, one side of the second resistor and the capacitor electrically connected to the drain, the other side of the second resistor and the capacitor connected to the ground terminal to reduce noises interfering the controller.

Assignees

• Delta Electronics Inc

Inventors

• Wang Ming-Whang

Classifications

• H02H3/162 Primary

  for AC systems · CPC title

• H02H5/105

  responsive to deterioration or interruption of earth connection (for preventing switching-on H02H11/001) · CPC title