Transmitting and receiving digital and analog signals across an isolator using amplitude modulation

A method for conveying a digital signal and a first analog signal across an isolation material from a first system to a second system, the method comprising:

• modulating the digital signal into a first modulated signal, wherein modulating the digital signal into the first modulated signal comprises:
• (i) generating a periodic waveform having a frequency indicative of the digital signal;
• and
• (ii) modulating the periodic waveform with a second analog signal to generate the first modulated signal such that the first modulated signal has a pulse width indicative of the second analog signal;
• modulating the first modulated signal in accordance with the first analog signal to produce a second modulated signal;
• transmitting the second modulated signal across the isolation material as a radiation;
• receiving the radiation;
• generating a received electrical signal in accordance with the radiation;
• branching out the received electrical signal to a first parallel branch so as to reconstruct the digital signal from the received electrical signal;
• and
• branching out the received electrical signal to a second parallel branch so as to reconstruct the first analog signal.

An isolator system adapted to convey a digital signal, a first analog signal and a second analog signal from a first semiconductor die to a second semiconductor die isolated from the first semiconductor die, the isolator system comprising:

• a periodic wave generator formed within the first semiconductor die, the periodic wave generator configured to generate a periodic wave signal having a frequency in accordance with the digital signal;
• a first modulator configured to modulate the periodic wave signal in accordance with the first analog signal into a first modulated pulse signal having a pulse width indicative of the first analog signal;
• a second modulator configured to modulate the first modulated pulse signal into a second modulated pulse signal such that the second modulated pulse signal has an amplitude substantially representative of the second analog signal;
• a transmitter circuit formed within the first semiconductor die, the transmitter circuit configured to transmit the second modulated pulse signal to the second semiconductor die;
• a receiver formed within the second semiconductor die, wherein the receiver is configured to generate a received modulated signal in accordance with the second modulated pulse signal received by the receiver;
• a frequency detector circuit formed within the second semiconductor die, the frequency detector circuit being coupled to the receiver and configured to demodulate the received modulated signal so as to regenerate the digital signal and the first analog signal;
• and
• an amplitude detection circuit formed within the second semiconductor die, the amplitude detection circuit being configured to demodulate the received modulated signal so as to regenerate the second analog signal.