Battery-less multi-turn absolute rotary encoder using capacitor

• US 20200132508A1
• Filed: 10/28/2018
• Published: 04/30/2020
• Est. Priority Date: 10/28/2018
• Status: Abandoned Application

• Current Assignee: Hui Li
• Original Assignee: Hui Li
• Inventors: Li, Hui
• Application Number:
  US16/172,824
• Publication Number:
  US 20200132508A1
• Time in Patent Office: Days
• CPC Class Codes: G01D 2205/26 Details of encoders or position sensors specially adapted to detect rotation beyond a full turn of 360°, e.g. multi-rotation
• CPC Class Codes: G01D 5/145 influenced by the relative movement between the Hall device and magnetic fields see G01R33/06
• CPC Class Codes: H02K 11/215 Magnetic effect devices, e.g. Hall-effect or magneto-resistive elements

Abstract

The present invention pertains to a multi-turn rotary encoder that can maintain multi-turn data without the use of a back-up battery. By integrating a capacitor into the main input power circuit of the encoder, the capacitor power can delay the shut off of the encoder microcontroller and sensor, allowing enough time for the rotary motion to stop before storing the single and multi-turn absolute position information. The invention also includes circuits to detect main power shut off and analog circuits to monitor input power voltage. After capacitor voltage drops below certain level, microcontroller saves single and multi-turn position and shuts down. When powering back up, the encoder reads the instantaneous position and compares with previously saved position, then the difference is calculated to determine current multi-turn position to begin normal operation.

Claims

1. A battery-less multi-turn rotary encoder comprising:

a capacitor power circuit to maintain power to the encoder microcontroller when main input power is shut off;

a power circuit from the capacitor to the absolute position sensor so that when main input power is shut off, the capacitor power can maintain power to the absolute position sensor.

2. The battery-less multi-turn rotary encoder in accordance with claim 1, where a dedicated circuit is used by the microcontroller to detect when the main input power is switched off.

3. The multi-turn rotary encoder in accordance with claim 1, where the capacitor and main power input are both connected to a linear regulator, where the regulator outputs a fixed DC voltage for the microcontroller and absolute position sensor.

4. The multi-turn rotary encoder in accordance with claim 1, where the main power input and capacitor power is connected to a microcontroller A/D input port, with or without a divider circuit with a parallel capacitor, so the microcontroller can read and monitor the voltage of main input power or capacitor power.

5. The multi turn rotary encoder in accordance with claim 1, where after the main input power is switched off, a capacitor voltage independently supports the encoder operation, and when capacitor voltage drops below a certain level, the microcontroller saves current single and multi-turn position to microcontroller internal or external memory.

6. The multi turn rotary encoder in accordance with claim 1 where the microcontroller is instead a microprocessor, DSP, FPGA or any type of integrated circuit that can be used to calculate encoder position and has the I/O peripherals necessary to support operation per claims 1˜

5.