System and method for starting up a high density isolated DC-to-DC power converter

1. A DC-to-DC power converter comprising:

a transformer comprising a primary side and a secondary side;

a primary circuit electrically coupled to the primary side of the transformer, the primary circuit comprising (i) at least one gate driver, (ii) a bias voltage generator, and (iii) a primary microcontroller electrically coupled to the bias voltage generator and configured to receive a first bias voltage supplied by the bias voltage generator, the primary microcontroller configured to provide a first energizing signal to the at least one gate driver in response to the first bias voltage; and

a secondary circuit electrically coupled to the secondary side of the transformer, the secondary circuit comprising a secondary microcontroller communicatively coupled to the primary microcontroller, the secondary microcontroller configured to receive a second bias voltage caused by the first energizing signal, the secondary microcontroller further configured to provide, in response to the second bias voltage, a second energizing signal to the at least one gate driver in response to the second bias voltage, the secondary microcontroller further configured to provide, in response to the second bias voltage, an instruction to the primary microcontroller that causes the primary microcontroller to relinquish control of the primary circuit to the secondary microcontroller.

2. The DC-to-DC power converter of claim 1 , wherein the secondary circuit further comprises a step-down converter electrically coupled between at least one of (i) the secondary side of the transformer and the secondary microcontroller and (ii) an output voltage bus of the DC-to-DC power converter and the secondary microcontroller, the step-down converter arranged to generate the second bias voltage.

3. The DC-to-DC power converter of claim 1 , further comprising a first isolation circuit coupled between the primary microcontroller and the secondary microcontroller, the secondary microcontroller configured to route the second energizing signal to the at least one gate driver through the first isolation circuit.

4. The DC-to-DC power converter of claim 1 , further comprising a second isolation circuit coupled between the primary microcontroller and the secondary microcontroller, the secondary microcontroller configured to route the instruction to relinquish control of the primary circuit through the second isolation circuit.

5. The DC-to-DC power converter of claim 1 , wherein the secondary circuit further comprises a rectifier circuit electrically coupled between the secondary side of the transformer and an output voltage bus.

6. The DC-to-DC power converter of claim 1 , further comprising a bias winding coupled to the bias voltage generator.

7. The DC-to-DC power converter of claim 1 , wherein the first energizing signal is a series of fixed frequency, constant on-time pulses, and wherein the second energizing signal is at least one of (i) pulse width modulated (PWM) signals and (ii) pulse frequency modulated (PFM) signals.

8. The DC-to-DC power converter of claim 1 , wherein the bias voltage generator is a linear regulator selected form the group consisting of a low-dropout regulator, a fixed regulator, a variable regulator, and a series regulator.

9. A DC-to-DC power converter comprising:

a transformer comprising a primary side and a secondary side;

a primary circuit electrically coupled to the primary side of the transformer, the primary circuit including a primary microcontroller configured to generate a first energizing signal that energizes a portion of the primary circuit; and

a secondary circuit electrically coupled to the secondary side of the transformer, the secondary circuit including a secondary microcontroller communicatively coupled to the primary microcontroller, the secondary microcontroller configured to provide, in response to a bias voltage caused by the first energizing signal, an instruction to the primary microcontroller that causes the primary microcontroller to relinquish control of the primary circuit to the secondary microcontroller, the secondary microcontroller further configured to provide a second energizing signal to the portion of the primary circuit.

10. The DC-to-DC power converter of claim 9 , wherein the secondary circuit further includes a step-down converter electrically coupled between the secondary side of the transformer and the secondary microcontroller, the step-down converter configured to step an output voltage induced in the secondary side of the transfer down to the bias voltage.

11. The DC-to-DC power converter of claim 9 , further comprising a first isolation circuit coupled between the primary microcontroller and the secondary microcontroller, the secondary microcontroller configured to provide the second energizing signal to the portion of the primary circuit through the first isolation circuit.

12. The DC-to-DC power converter of claim 9 , further comprising a second isolation circuit coupled between the primary microcontroller and the secondary microcontroller, the secondary microcontroller configured to route the instruction to relinquish control of the primary circuit through the second isolation circuit.

13. The DC-to-DC power converter of claim 9 , wherein the secondary circuit further comprises a rectifier circuit electrically coupled between the secondary side of the transformer and an output voltage bus.

14. The DC-to-DC power converter of claim 9 , further comprising a bias voltage generator and a bias winding, the bias voltage generator electrically coupled to the primary microcontroller through the bias winding.

15. The DC-to-DC power converter of claim 9 , wherein the first energizing signal is a series of fixed frequency, constant on time pulses, and wherein the second energizing signal is at least one of i) pulse width modulated (PWM) signals and ii) pulse frequency modulated (PFM) signals.

16. A method of operating a DC-to-DC power converter, the method comprising:

receiving, by a primary microcontroller disposed within a primary circuit of the DC-to-DC power converter, a first bias voltage;

generating, by the primary microcontroller and in response to the first bias voltage, a first energizing signal that energizes a portion of the primary circuit;

sending, by a secondary microcontroller disposed within a second circuit and in response to a bias voltage caused by the first energizing signal, an instruction to the primary microcontroller to relinquish control of the primary circuit to the secondary microcontroller;

receiving, by the primary microcontroller, the instruction to relinquish control of the primary circuit to the secondary microcontroller; and

transmitting, by the secondary microcontroller, a second energizing signal to the portion of the primary circuit.

17. The method of claim 16 , further comprising receiving, by the secondary microcontroller, the bias voltage from a non-isolated step-down converter coupled to a secondary side of a transformer, the transformer coupled between the primary circuit and the secondary circuit.

18. The method of claim 17 , further comprising routing, by the secondary microcontroller, the second energizing signal to the portion of the primary circuit through a first digital isolator coupled between the primary circuit and the secondary circuit.

19. The method of claim 18 , further comprising routing, by the secondary microcontroller, the instruction to relinquish control of the primary circuit through a second digital isolator coupled between the primary circuit and the secondary circuit.

20. The method of claim 17 , further comprising routing, by the secondary microcontroller, the second energizing signal to the portion of the primary circuit through a first optocoupler coupled between the primary circuit and the secondary circuit.