Encoder having function of adjusting threshold value of comparator and method for controlling encoder
First Claim
1. An encoder comprising:
- a voltage generation circuit connected to a power supply through a diode and having a variable resistor, the voltage generation circuit configured to output a voltage (I×
R) corresponding to a current I flowing through the diode and a resistance value R of the variable resistor, as a threshold value Vth;
a comparator configured to perform a comparison between an analog signal inputted from a detector for detecting rotation of a motor and the threshold value inputted from the voltage generation circuit, and output a comparison result as a comparator output;
an A/D converter configured to convert the analog signal into a digital signal;
a threshold value determination circuit configured to calculate an average value of a maximum value Vmax and a minimum value Vmin of the digital signal, as a new threshold value; and
a resistance value change circuit configured to change a resistance value R of the variable resistor, such that the calculated new threshold value is inputted from the voltage generation circuit to the comparator.
1 Assignment
0 Petitions
Accused Products
Abstract
An encoder according to an embodiment of this disclosure includes a voltage generation circuit connected to a power supply through a diode and having a variable resistor, the voltage generation circuit outputting a voltage corresponding to a current flowing through the diode and a resistance value of the variable resistor, as a threshold value; a comparator for comparing an analog signal inputted from a detector for detecting rotation of a motor with the threshold value inputted from the voltage generation circuit, and outputting a comparison result as a comparator output; an A/D converter for converting the analog signal into a digital signal; a threshold value determination circuit for calculating a new threshold value using the digital signal; and a resistance value change circuit for changing a resistance value of the variable resistor, such that the calculated new threshold value is inputted from the voltage generation circuit to the comparator.
20 Citations
8 Claims
-
1. An encoder comprising:
-
a voltage generation circuit connected to a power supply through a diode and having a variable resistor, the voltage generation circuit configured to output a voltage (I×
R) corresponding to a current I flowing through the diode and a resistance value R of the variable resistor, as a threshold value Vth;a comparator configured to perform a comparison between an analog signal inputted from a detector for detecting rotation of a motor and the threshold value inputted from the voltage generation circuit, and output a comparison result as a comparator output; an A/D converter configured to convert the analog signal into a digital signal; a threshold value determination circuit configured to calculate an average value of a maximum value Vmax and a minimum value Vmin of the digital signal, as a new threshold value; and a resistance value change circuit configured to change a resistance value R of the variable resistor, such that the calculated new threshold value is inputted from the voltage generation circuit to the comparator. - View Dependent Claims (2)
-
-
3. An encoder comprising:
-
a voltage generation circuit connected to a power supply through a diode and having a variable resistor, the voltage generation circuit configured to output a voltage (I×
R) corresponding to a current I flowing through the diode and a resistance value R of the variable resistor, as a threshold value Vth;a plurality of comparators configured to perform comparisons between each of analog signals inputted from detectors for detecting rotation of motors and the threshold value inputted from the voltage generation circuit, and output comparison results as comparator outputs; a plurality of A/D converters configured to convert the analog signals into digital signals; a threshold value determination circuit for calculating a minimum value of average values each of which is calculated from a maximum value and a minimum value of each of the digital signals, as a new threshold value; and a resistance value change circuit configured to change a resistance value R of the variable resistor, such that the calculated new threshold value is inputted from the voltage generation circuit to the comparators. - View Dependent Claims (4)
-
-
5. A method for controlling an encoder comprising the steps of:
-
inputting an output voltage of a voltage generation circuit to a comparator, wherein the voltage generation circuit having a variable resistor is connected to a power supply through a diode and outputs the output voltage (I×
R) corresponding to a current I flowing through the diode and a resistance value R of the variable resistor, as a threshold value Vth;inputting an analog signal from a detector of the encoder to the comparator and an A/D converter; converting the analog signal into a digital signal by the A/D converter; performing a comparison between the analog signal and the threshold value, and outputting a comparison result as a comparator output by the comparator; calculating an average value of a maximum value Vmax and a minimum value Vmin of the digital signal, as a new threshold value by a threshold value determination circuit; and changing a resistance value R of the variable resistor of the voltage generation circuit by a resistance value change circuit, such that the calculated new threshold value is inputted from the voltage generation circuit to the comparator. - View Dependent Claims (6)
-
-
7. A method for controlling an encoder comprising the steps of:
-
inputting an output voltage of a voltage generation circuit to a plurality of comparators, wherein the voltage generation circuit having a variable resistor is connected to a power supply through a diode and outputs the output voltage (I×
R) corresponding to a current I flowing through the diode and a resistance value R of the variable resistor, as a threshold value Vth;inputting analog signals from a plurality of detectors of the encoder to a plurality of comparators and a plurality of A/D converters; converting the analog signals into digital signals by the A/D converters; performing comparisons between each of the analog signals and the threshold value, and outputting comparison results as comparator outputs by the comparators; calculating an average value of a maximum value Vmax and a minimum value Vmin of each of the digital signals as a new threshold value by a threshold value determination circuit; and changing a resistance value R of the variable resistor of the voltage generation circuit by a resistance value change circuit, such that the calculated new threshold value is inputted from the voltage generation circuit to the comparators. - View Dependent Claims (8)
-
Specification