Voltage conversion and charging from low bipolar input voltage

A circuit comprising:

• a transformer configured with a primary winding and a secondary winding that are driven from a voltage supplied by a thermoelectric generator (TEG);
• and
• a flyback converter stage (FCS) operatively coupled to the transformer to generate an output voltage greater than the voltage supplied by the TEG, the FCS comprising:
• a first transistor device operatively coupled in series with the primary winding of the transformer to excite the primary winding and to generate an AC output on the secondary winding when the output voltage is below a predetermined threshold;
• and
• a second transistor device operatively coupled in parallel with the first transistor device, the second transistor device operatively coupled in series with the primary winding of the transformer to excite the primary winding and to generate an AC output on the secondary winding when the output voltage is above the predetermined threshold.

A circuit comprising:

• a transformer configured with a primary winding and a secondary winding that are driven from a voltage supplied by a thermoelectric generator (TEG);
• a bipolar startup stage (BSS) operatively coupled to the transformer to generate an intermediate voltage greater than the voltage supplied by the TEG, the BSS comprising:
• a first transistor device operatively coupled in series with the primary winding of the transformer to form an oscillator circuit with an inductance of the secondary winding when the voltage supplied by the TEG is positive;
• and
• a second transistor device operatively coupled to the secondary winding of the transformer to enable the oscillator circuit to oscillate when the voltage supplied by the TEG is negative;
• a flyback converter stage (FCS) operatively coupled to the transformer to generate an output voltage greater than the intermediate voltage supplied by the BSS, the FCS comprising:
• a third transistor device operatively coupled in series with the primary winding of the transformer to excite the primary winding and to generate an AC output on the secondary winding when the output voltage is below a predetermined threshold;
• and
• a fourth transistor device operatively coupled in parallel with the third transistor device, the fourth transistor device operatively coupled in series with the primary winding of the transformer to excite the primary winding and to generate an AC output on the secondary winding when the output voltage is above the predetermined threshold.