Signal transmission method
View Patent ↗A data transmission method superimposes a spread code onto data in order to synthesize a first signal. The method changes the switching frequency of a switching power supply based on the first signal, transmitting the second signal to a plurality of semiconductor apparatuses (satellite apparatuses) via an output line of the switching power supply. The method changes the DC output voltage level of the second signal on the output line of the switching power supply wherein a satellite apparatus may use the second signal for controlling and instructing the satellite apparatuses to make the satellite apparatus shift, for example, from the stopped state or the sand-by mode to the normal operation mode so that the satellite apparatus may receive the first signal.
1. A signal transmission method, comprising:
modulating a switching frequency of a switching device with a first signal;
superimposing the first signal onto an output line of a switching power supply; and
changing a voltage level on the output line of the switching power supply, thereby transmitting a second signal via the output line of the switching power supply.
2. The signal transmission method according to claim 1 , wherein superimposing the first signal onto the output line of the switching power supply is based upon at least one of a predetermined voltage level on the output line and within a predetermined voltage range.
3. The signal transmission method according to claim 1 , further comprising superimposing a spread code onto a signal to be transmitted to generate the first signal.
4. The signal transmission method according to claim 3 , wherein the switching frequency is determined by an oscillator circuit that charges and discharges a capacitor between predetermined voltage values with a constant current, and the constant current value is changed by data of continuous m bits in a signal obtained by superimposing the spread code onto the signal to be transmitted, wherein said m is a nonnegative integer.
5. The signal transmission method according to claim 1 , further comprising controlling a first DC-DC converter based upon the first and second signals.
6. The signal transmission method according to claim 5 , wherein a second DC-DC converter is connected to the output line of the switching power supply, and the first and second signals are used to control the second DC-DC converter.
7. The signal transmission method according to claim 1 , further comprising transmitting a synchronization signal on a signal line different from the output line of the switching power supply, the synchronization signal operable to synchronize the second signal superimposed onto the output line of the switching power supply.