Method and apparatus for powering and loading software into a battery-less electronic device
Automated software loading into a battery-less mobile phone is accomplished through attachment of a special non-standard USB On-The-Go cable to a serial connector of the mobile phone, thereby delivering power supply and unique signals for placing the phone in a special mode of operation used for production or distribution. In operation, when a unique non-standard voltage is asserted on the identification (ID) pin of the USB connector interface, it is detected by special circuitry in the serial connector. The circuitry then enables power supply to the battery-less phone and generates a turn-on signal directing the mobile phone to automatically power-on and enter into a particular state of operation, for example a test or software loading mode. Because this process is automatic, the efficiency of software loading or testing during production or distribution of the mobile device is improved.
1. A circuit comprising:
a comparator receiving a reference voltage at a first input of the comparator and an identification signal from a serial bus interface at a second input of the comparator, and generating a comparison signal on an output of the comparator when the identification signal is non-standard as indicated by a comparison to the reference voltage, wherein the output of the comparator is coupled to an electronic device that enters a unique mode of operation in response to receiving the comparison signal; and
a voltage regulator receiving a power signal from the serial bus interface at a first input of the voltage regulator and being electrically coupled to the output of the comparator at a second input of the voltage regulator, wherein the voltage regulator is enabled to generate a power supply on an output of the voltage regulator in response to the comparison signal.
2. The circuit of claim 1 , wherein the comparison signal indicates to the electronic device to automatically turn on and enter into the unique mode of operation.
3. The circuit of claim 1 , wherein the unique mode of operation indicates a software download mode of operation for the electronic device.
4. The circuit of claim 1 , wherein the unique mode of operation indicates a testing mode of operation for the electronic device.
5. The circuit of claim 1 , wherein the comparison signal generates an interrupt within the electronic device to begin software loading via the serial bus interface.
6. The circuit of claim 1 , wherein the serial bus interface is a USB On-The-Go connector.
7. The circuit of claim 1 , wherein the comparator is a depletion mode comparator.
8. The circuit of claim 1 , wherein the electronic device is capable of being battery-powered but a battery is not present and powering the electronic device when entering the unique mode of operation.
9. A method for powering and placing a battery-powered electronic device in a specialized mode of operation comprising:
detecting a unique voltage condition on an information pin of a serial bus interface to the electronic device;
automatically enabling power supply to power the electronic device in response to detecting the unique voltage condition;
automatically placing the electronic device in a special mode of operation in response to detecting the unique voltage condition; and
generating an interrupt within the electronic device to begin software loading in response to detecting the unique voltage condition.
10. The method of claim 9 , further comprising generating signal causing the electronic device to turn on in response to detecting the unique voltage condition.
11. The method of claim 9 , further comprising enabling the electronic device to enter into a testing mode of operation in response to detecting the unique voltage condition.
12. The method of claim 9 , wherein the serial bus interface is a USB On-The-Go connector.
13. The method of claim 9 , wherein the step of detecting is performed by a depletion mode comparator.
14. The method of claim 9 , further comprising detecting standard signals on the information pin that indicate the electronic device's role in communications over the serial bus interface.
15. The method of claim 9 , wherein the electronic device is capable of being battery-powered but a battery is not present and powering the electronic device when placed in the special mode of operation.
16. A method for powering and placing a battery-powered electronic device in a specialized mode of operation comprising:
detecting a unique voltage condition on an information pin of a serial bus interface to the electronic device;
automatically enabling power supply to power the electronic device in response to detecting the unique voltage condition;
automatically placing the electronic device in a special mode of operation in response to detecting the unique voltage condition; and
enabling the electronic device to load software transmitted over the serial bus interface in response to detecting the unique voltage condition.