Analog to digital voltage measuring device
AssigneeAlpha Smart, Inc.
InventorBradley M. Daw
Life of this patent
Estimating the term…
Abstract
A voltage measuring circuit for measuring a voltage level of an unknown voltage source, including a capacitor configured for storing a charge from the unknown voltage source, a switch such as a transistor, configured to discharge the capacitor after the capacitor has reached a known threshold voltage, a microprocessor which controls the switch and measures the amount of time required to charge the capacitor to the threshold voltage, allowing the voltage level to be measured without disconnecting the capacitor from the circuit.
Claims27
A voltage measuring circuit configured for measuring a voltage level of an unknown voltage source, comprising:
- (a) a capacitor connected and configured to charge from the unknown voltage source;
- (b) a resistor connected between the unknown voltage source and the capacitor;
- (c) a switch, shunt-coupled to the capacitor, and configured for discharging the capacitor after the capacitor has reached a threshold voltage so as to enable the capacitor to be charged again;
- and,
- (d) a microcontroller configured to control the switch and measure an amount of time required to charge the capacitor to the threshold voltage through the resistor, the time required to charge the capacitor to the threshold voltage being used to determine the voltage level of the unknown voltage source using at least one stored calibration data value.
A method for measuring the voltage level of an unknown voltage source, comprising the steps of:
- (a) providing a resistor and a capacitor;
- (b) charging the capacitor from the unknown voltage source through the resistor to a threshold voltage;
- (c) providing a switch shunt-coupled to the capacitor;
- (d) measuring a length of time needed to charge the capacitor to the threshold voltage;
- (e) determining the voltage level of the unknown voltage source based on the length of time required to charge the capacitor to the threshold voltage using at least one stored calibration data value;
- and,
- (f) discharging the capacitor voltage after the capacitor charge has reached a threshold value using the switch without disconnecting the capacitor from the unknown voltage source.
A method for measuring the voltage level of an unknown voltage source, comprising the steps of:
- (a) providing a resistor and a capacitor;
- (b) charging the capacitor from the unknown voltage source through the resistor to a threshold voltage;
- (c) providing a switch shunt-coupled to the capacitor;
- (d) providing a microcontroller and determining a length of time needed to charge the capacitor to the threshold voltage using the microcontroller;
- (e) determining the voltage level of the unknown voltage source based on the length of time required to charge the capacitor to the threshold voltage determining the voltage level of the unknown voltage source using an a logarithmic function programmed into the microcontroller using the following formula:
- V Vt/(1−e(−t/R1C1))
- wherein
- V is the voltage of the unknown voltage source;
- Vt is the voltage of the capacitor at time t;
- e is the natural logarithmic number;
- t is the measured time taken to charge the capacitor;
- R1 is the value of the resistor used;
- and
- C1 is the value of the capacitor used;
- and,
- (f) discharging the capacitor voltage after the capacitor charge has reached a threshold value using the switch without disconnecting the capacitor from the unknown voltage source.
A method for measuring the voltage of an unknown voltage source using a microcontroller having a timer, comprising the steps of:
- (a) providing a capacitor and resistor, the capacitor connected to the unknown voltage source through the resistor;
- (b) charging the capacitor from the unknown voltage source through the resistor;
- (c) measuring a length of time needed to charge the capacitor using the timer;
- (d) determining the voltage of the unknown voltage source based on the length of time required to charge the capacitor;
- (e) discharging the capacitor voltage using a solid-state switching device without disconnecting the capacitor from the unknown voltage source after the microcontroller has determined that the capacitor voltage has reached a threshold value;
- (f) providing a transistor switching device;
- (g) connecting an output line of the microcontroller to a base of the transistor switching device;
- and,
- (h) bringing the output line from low to high after the microcontroller determines the capacitor is charged to the threshold voltage, which causes the transistor to go into saturation and discharges the capacitor.
A method for measuring the voltage of an unknown voltage source using a microcontroller having a timer, comprising the steps of:
- (a) providing a capacitor and a resistor, the capacitor connected to the unknown voltage source through the resistor;
- (b) charging the capacitor from the unknown voltage source through the resistor;
- (c) measuring a length of time needed to charge the capacitor using the timer;
- (d) determining the voltage of the unknown voltage source based on the length of time required to charge the capacitor using at least one stored calibration data value;
- and,
- (e) discharging the capacitor voltage using a solid-state switching device without disconnecting the capacitor from the unknown voltage source after the microcontroller has determined that the capacitor voltage has reached a threshold value.
Dependencies are inferred from the claim text.