Pillow speaker relay circuit, pillow speaker, and method for same
The present disclosure provides a method for determining a presence of a relay in a pillow speaker, including sampling a voltage of a relay drive line to detect a first feedback state; providing a control signal to activate the relay drive line; sampling a voltage of the relay drive line during activation to detect a second feedback state; and comparing the first feedback state and the second feedback state to detect a presence of a relay. In another aspect, a pillow speaker relay circuit includes a relay drive line with a relay terminal configured to connect to a relay such that current flows through the relay when the relay drive line is activated; a control circuit operable to activate the relay drive line, and a feedback detection circuit configured to detect a voltage of the relay drive line; and a controller to perform any of the disclosed methods.
1. A method for determining a presence of a relay in a pillow speaker, comprising:
sampling a voltage of a relay drive line to detect a first feedback state;
providing a control signal to activate the relay drive line;
sampling a voltage of the relay drive line during activation of the relay drive line to detect a second feedback state; and
comparing the first feedback state and the second feedback state to detect a presence of a relay if the first feedback state and the second feedback state are different.
2. The method of claim 1 , wherein the relay drive line is activated by connecting a relay terminal of the relay drive line to ground.
3. The method of claim 2 , wherein the relay terminal is connected to ground using a transistor.
4. The method of claim 3 , wherein the transistor is an N-channel enhancement mode metal oxide semiconductor field-effect transistor (N-channel MOSFET or NFET).
5. The method of claim 1 , wherein the relay drive line is activated by connecting a relay terminal of the relay drive line to a voltage source.
6. The method of claim 5 , wherein the voltage source has a voltage sufficient to actuate the relay.
7. The method of claim 1 , wherein the voltage is sampled by way of a test line.
8. The method of claim 7 , wherein the test line comprises a Schmitt trigger, a buffer, or an inverter.
9. The method of claim 1 , further comprising providing a confirmation signal when the first feedback state is different from the second feedback state.
10. The method of claim 9 , wherein the confirmation signal is provided to a patient interface device.
11. The method of claim 1 , further comprising receiving an input signal from a patient interface device.
12. The method of claim 1 , wherein the control signal is provided for a pre-determined period of time selected to be less than an operate time of a relay.
13. A pillow speaker relay circuit, comprising:
a relay drive line having a relay terminal configured to connect to a relay such that current flows through the relay when the relay drive line is activated;
a control circuit operable to activate the relay drive line;
a feedback detection circuit configured to detect a voltage of the relay drive line; and
a controller configured to:
sample a voltage of the relay drive line to detect a first feedback state;
provide a control signal to the control circuit to activate the relay drive line; and
sample a voltage of the relay drive line during activation to detect a second feedback state.
14. A pillow speaker, comprising:
a plurality of pillow speaker relay circuits according to claim 13 ;
a plurality of logic gates arranged in a cascade, wherein the feedback detection circuit of each pillow speaker relay circuit is connected to an input of the logic gate cascade to provide a single feedback test point.
15. The pillow speaker of claim 14 , further comprising a base station (HUB) and a patient interaction device (PID) in electronic communication with the HUB; and
wherein the plurality of pillow speaker relay circuits and the plurality of logic gates are housed within the HUB.