Control system and method for sensor management

Patent metadata

Field	Value
Publication number	US-9494542-B2
Application number	US-201414155630-A
Country	US
Kind code	B2
Filing date	Jan 15, 2014
Priority date	Jan 17, 2013
Publication date	Nov 15, 2016
Grant date	Nov 15, 2016

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.

First claim

The invention claimed is:

1. A measuring circuit, comprising:
a control block configured to control said circuit;
a time base configured to provide a clock signal (f clk ) in order to time said circuit;
a sensor block comprising an oscillator, a first variable-value electronic component (C s ), and a second fixed-value electronic component (C 0 ), the sensor block being configured to provide an output signal;
a first counting block, which is timed to a clock frequency; and
a second counting block, which is timed by a frequency of the output signal of the sensor block,
wherein the first variable-value electronic component (C s ) and a second fixed-value electronic component (C 0 ) each comprise a first terminal and a second terminal, and are connected in parallel to the oscillator by means of commutation means,
wherein the first variable-value electronic component (C s ) is configured to provide a first signal, and the second fixed-value electronic component (C 0 ) is configured to provide a second signal,
wherein the commutation means comprises a first controllable switch (T 1 ) and a second controllable switch (T 2 ), which are connected in series between the first terminal of the first variable-value electronic component (C s ) and the first terminal of the second fixed-value electronic component (C 0 ),
wherein the sensor block is further configured to provide, as the output signal,
the first signal, a frequency of which is representative of a measured physical quantity, or
the second signal, a frequency of which is a reference frequency,

wherein the control block is further configured to control 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
wherein a 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 a frequency (F ref ) of the second signal during the first phase and by a 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 commutation means further comprises a third controllable switch (T 3 ) and a fourth controllable switch (T 4 ), which are connected in series between the second terminal of the first variable-value electronic component (C s ) and the second terminal of the second fixed-value electronic component (C 0 ), and
wherein a connection point between the first controllable switch (T 1 ) and the second controllable switch (T 2 ), and the connection point between the third controllable switch (T 3 ) and the fourth controllable switch (T 4 ), are connected to the oscillator.

8. The measuring circuit according to claim 1 , wherein the first component and the second component are capacitors.

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 1 , wherein the first component and the second component are resistors.

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 1 , wherein the first component and the second component are inductance coils.

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

14. The measuring circuit according claim 1 , wherein the sensor block is configured to measure a degree of moisture.

15. The measuring circuit according to claim 1 , further comprising a linearization circuit.

16. A method for management of a measuring circuit,
the measuring circuit comprising:
a control block configured to control said circuit,
a time base configured to provide a clock signal in order to time said circuit,
a sensor block comprising an oscillator, a first variable-value electronic component (C s ), and a second fixed-value electronic component (C 0 ), the sensor block being configured to provide an output signal,
a first counting block, which is timed to a clock frequency, and
a second counting block, which is timed by a frequency of the output signal of the sensor block,
wherein the first variable-value electronic component (C s ) and a second fixed-value electronic component (C 0 ) each comprise a first terminal and a second terminal, and are connected in parallel to the oscillator by means of commutation means,
wherein the first variable-value electronic component (C s ) is configured to provide a first signal, and the second fixed-value electronic component (C 0 ) is configured to provide a second signal,
wherein the commutation means comprises a first controllable switch (T 1 ) and a second controllable switch (T 2 ), which are connected in series between the first terminal of the first variable-value electronic component (C s ) and the first terminal of the second fixed-value electronic component (C 0 ),
wherein the sensor block is further configured to provide, as the output signal, the first signal, a frequency (F s ) of which is representative of a measured physical quantity, or the second signal, a frequency (F ref ) of which is a reference frequency; and

the method the following steps:
1) selecting the second signal as the output signal of the sensor block;
2) starting counting of the first counting block and of the second counting block;
3) when the first counting block reaches a first predefined number (N clk ), resetting the first counting block to zero and stopping the counting of the second counting block;
4) selecting the first signal as the output signal of the sensor block;
5) starting the counting of the first counting block and the counting down of the second counting block from a 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 a value (N s ) counted by the first counting block; and

7) determining, from the value (N s ), a value of the physical quantity measured by the sensor block.

17. The method for management according to claim 16 , wherein the second predefined number is zero.

18. The method for management according to claim 16 , wherein the first predefined number (N clk ) is dependent upon a resolution of the counter.

19. The method for management according to claim 16 , further comprising linearizing a value counted by the first counting block as a function of the measured physical quantity by squaring said value counted by the first counting block.

20. A wearable/portable electronic object comprising the measuring circuit acc

Assignees

• Em Microelectronic Marin Sa

Inventors

• Novac Pinchas

Classifications

• G01D5/243

  influencing the phase or frequency of AC · CPC title

• G01N27/048

  for determining moisture content of the material · CPC title

• G01N27/228

  Circuits therefor (measuring capacitance per se G01R27/26) · CPC title

• G01N27/223

  for determining moisture content, e.g. humidity (rain detectors on vehicle windows B60S1/0825) · CPC title

• G01N27/028 Primary

  Circuits therefor (measuring impedance per se G01R27/02) · CPC title