CONTROL SYSTEM AND METHOD FOR SENSOR MANAGEMENT

• US 20140197849A1
• Filed: 01/15/2014
• Published: 07/17/2014
• Est. Priority Date: 01/17/2013
• Status: Active Grant

• Current Assignee: EM Microelectronic - Marin SA (The Swatch Group AG)
• Original Assignee: EM Microelectronic - Marin SA (The Swatch Group AG)
• Inventors: NOVAC, Pinchas
• Granted Patent: US 9,494,542 B2
• Time in Patent Office: Days
• US Class Current: 324/654
• CPC Class Codes: G01D 5/24 by varying capacitance
• CPC Class Codes: G01D 5/243 influencing the phase or frequency of ac
• CPC Class Codes: G01N 27/028 Circuits therefor measuring impedance per se G01R27/02
• CPC Class Codes: G01N 27/048 for determining moisture content of the material
• CPC Class Codes: G01N 27/223 for determining moisture content, e.g. humidity rain detectors on vehicle windows B60S1/0825
• CPC Class Codes: G01N 27/228 Circuits therefor measuring capacitance per se G01R27/26

Abstract

The invention relates to a measuring circuit comprising a control block for controlling said circuit, a time base for providing a clock signal (f_clk) in order to time said circuit, a sensor block which is designed to provide an output signal, said measuring circuit comprising in addition a first counting block which is timed to the clock frequency and a second counting block which is timed by the frequency of the output signal of the sensor block.

Claims

1. A measuring circuit comprising a control block for controlling said circuit, a time base for providing a clock signal (f_clk) in order to time said circuit, a sensor block which is designed to provide an output signal, said measuring circuit comprising in addition a first counting block which is timed to the clock frequency and a second counting block which is timed by the frequency of the output signal of the sensor block, wherein the sensor block is designed to provide, as output signal, a first signal, the frequency of which is representative of the measured physical quantity or a second signal, the frequency of which is a reference frequency and in that the control block controls the measuring circuit so that the first and second counting blocks function according to a first phase in which the first and second counting blocks count and a second phase in which the first counting block counts and the second counting block counts down and in that the timing frequency of the second counting block during the first phase is different from that during the second phase.

2. The measuring circuit according to claim 1, wherein the second counting block is timed by the frequency (F_ref) of the second signal during the first phase and by the frequency (F_S) of the first signal during the second phase.

3. The measuring circuit according to claim 1, wherein the control block comprises a control circuit and a sequencer block.

4. The measuring circuit according to claim 2, wherein the control block comprises a control circuit and a sequencer block.

5. The measuring circuit according to claim 3, wherein the second counting block comprises a zero detector connected to the sequencer block.

6. The measuring circuit according to claim 4, wherein the second counting block comprises a zero detector connected to the sequencer block.

7. The measuring circuit according to claim 1, wherein the sensor block comprises an oscillator, a first variable-value electronic component (C_S) and a second fixed-value electronic component (C₀), the first and the second electronic component being connected in parallel to the oscillator by means of commutation means and in that the first electronic component makes it possible to provide the first signal and in that the second electronic component makes it possible to provide the second signal.

8. The measuring circuit according to claim 7, wherein the first component (C_S) and the second component (C₀) each comprise a first terminal and a second terminal and in that the commutation means comprise a first (T1) and a second (T2) controllable switch, which are connected in series between the first terminal of the first component and the first terminal of the second component and a third (T3) and a fourth (T4) controllable switch, which are connected in series between the second terminal of the first component and the second terminal of the second component, the connection point between the first and the second controllable switch and the connection point between the third and the fourth controllable switch being connected to the oscillator unit.

9. The measuring circuit according to claim 7, wherein the first component and the second component are capacitors.

10. The measuring circuit according to claim 8, wherein the first component and the second component are capacitors.

11. The measuring circuit according to claim 7, wherein the first component and the second component are resistors.

12. The measuring circuit according to claim 8, wherein the first component and the second component are resistors.

13. The measuring circuit according to claim 7, wherein the first component and the second component are inductance coils.

14. The measuring circuit according to claim 8, wherein the first component and the second component are inductance coils.

15. The measuring circuit according claim 1, wherein the sensor block (106) is able to measure the degree of moisture.

16. The measuring circuit according to claim 1, wherein it comprises in addition a linearization circuit.

21. The wearable/portable electronic object, wherein it comprises the measuring circuit according to claim 1.

17. The method for management of a measuring circuit comprising a control block for controlling said circuit, a time base for providing a clock signal in order to time said circuit, a sensor block which is designed to provide an output signal, said measuring circuit comprising in addition a first counting block which is timed to the clock frequency and a second counting block which is timed by the frequency of the output signal of the sensor block, wherein the sensor block is designed to provide, as output signal, a first signal, the frequency (F_S) of which is representative of the measured physical quantity or a second signal, the frequency (F_ref) of which is a reference frequency and in that said method comprises the following steps:

1) selecting the second signal, the frequency of which is a reference frequency as output signal of the sensor block;

2) starting the counting of the first counting block which is timed by the clock signal and of the second counting block which is timed by the output signal of the sensor block;

3) when the first counting block reaches a first predefined number (N_clk), it is reset at zero and the second counting block stops counting;

4) selecting the first signal, the frequency of which is representative of the measured physical quantity as output signal of the sensor block;

5) starting the counting of the first counting block which is timed by the clock signal and the counting down of the second counting block from the value (N_ref) counted during step

     3), said second counting block being timed by the output signal of the sensor block;

6) when the second counting block reaches a second predefined number;

stopping the counting of the first counting block and the counting down of the second counting block and

saving the value (N_S) counted by the first counting block;

7) determining, from the value (N_S) counted by the first counting block, the value of the physical quantity measured by the sensor block.

18. The method for management according to claim 17, wherein the second predefined number (N_S) is zero.

19. The method for management according to claim 17, wherein the first predefined number (N_clk) is dependent upon the resolution of the counter.

20. The method for management according to claim 17, wherein it comprises in addition a final step which is intended to linearize the value counted by the first counting block as a function of the measured physical quantity, this step consisting of squaring said value counted by the first counting block.