Self-oscillating full bridge driver IC

1. A control circuit for controlling switching devices for supplying power to a load, comprising:

a high-side driver for controlling a high-side switching device and a low-side driver for controlling a low-side switching device;

said high-side driver having a high-side floating supply terminal and a high-side floating supply return terminal;

a precharging circuit connected to said high-side driver for contributing power to said high-side driver; and

a timing circuit, said timing circuit delivering drive timing signals to said high-side driver to cause said high-side driver to drive said high-side switching device,

said timing circuit further delivering precharge timing signals for controlling said precharging circuit so as to power said high-side driver before said high-side driver receives said drive signals.

2. The control circuit of claim 1 , wherein said precharging circuit comprises:

a bootstrap capacitor connected between said high-side floating supply and floating supply return terminals, and

a bootstrap circuit connected to said high-side floating supply and floating supply terminal for supplying current to charge to said bootstrap capacitor in response to said precharge timing signals.

3. A control circuit for controlling switching devices for supplying power to a load, comprising:

a pair of high-side drivers for controlling respective high-side switching devices and a pair of low-side drivers for controlling respective low-side switching devices;

said high-side drivers each having a high-side floating supply terminal and a high-side floating supply return terminal;

respective precharging circuits connected to said high-side drivers; for contributing power to said high-side drivers;

a timing circuit, said timing circuit delivering drive timing signals to said high-side drivers to cause said high-side drivers to drive said high-side switching devices,

said timing circuit further delivering precharge timing signals for controlling said precharging circuits so that said high-side drivers are powered before said high-side drivers receive said drive timing signals.

4. The control circuit of claim 3 , wherein said precharging circuits comprise:

respective bootstrap capacitors being connected between said high-side floating supply and floating supply return terminals of each said high-side driver; and

a bootstrap circuit connected to each said high-side floating supply terminal for supplying current to charge the corresponding said bootstrap capacitor in response to said precharge timing signals.

5. The control circuit of claim 4 , wherein said timing circuit delivers timing signals simultaneously to both said low-side drivers and thereby actuates both said precharging circuits before supplying said drive timing signals to said high-side drivers.

6. The control circuit of claim 3 , wherein said timing circuit delivers timing signals simultaneously to both said low-side drivers and thereby actuates both said precharging circuits before supplying said drive timing signals to said high-side drivers.

7. A method of controlling switching devices for supplying power to a load, said switching devices comprising:

a high-side driver for controlling a high-side switching device and a low-side driver for controlling a low-side switching device;

said high-side driver having a high-side floating supply terminal and a high-side floating supply return terminal;

a precharging circuit connected to said high-side driver for contributing power to said high-side driver;

the method comprising the steps of:

delivering drive signals to said high-side driver from a timing circuit to cause said high-side driver to drive said high-side switching device, and

controlling said precharging circuit with a predetermined signal from said timing circuit so as to power said high-side driver before said high-side driver receives said drive signals.

8. The method of claims 7 , wherein said step of controlling said precharging circuit includes the step of charging a capacitor connected between said high-side floating supply and floating-supply return terminals.

9. A method of controlling switching devices for supplying power to a load, said switching devices comprising:

a pair of high-side drivers for controlling respective high-side switching devices and a pair of low-side drivers for controlling respective low-side switching devices;

said high-side drivers each having a high-side floating supply terminal and a high-side floating supply return terminal;

respective precharging circuits being connected to each said high-side driver, for contributing power to the corresponding said high-side driver;

the method comprising the steps of:

delivering drive signals to said high-side drivers from a timing circuit to cause said high-side drivers to drive said high-side switching devices, and

controlling said precharging circuits with a predetermined signal from said timing circuit so as to power said high-side drivers before said high-side drivers receive said drive signals.

10. The method of claim 9 , wherein said step of controlling said precharging circuits includes the step of charging respective capacitors connected between said high-side floating supply and floating supply return terminals.

11. The method of claim 10 , wherein said controlling step includes simultaneously driving both said low-side drivers and thereby actuating both said precharging circuits before delivering said drive signals to said high-side drivers.

12. The method of claim 9 , wherein said controlling step includes simultaneously driving both said low-side drivers and thereby actuating both said precharging circuits before delivering said drive signals to said high-side drivers.