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A frequency-controlled load driver circuit includes a steady-state and a transient operational mode. A switching driver switches a load current to a solenoid at a set switching frequency during a steady-state operational mode. An analog-to-digital converter (ADC) oversamples a sense resistor voltage

A frequency-controlled load driver circuit includes a steady-state and a transient operational mode. A switching driver switches a load current to a solenoid at a set switching frequency during a steady-state operational mode. An analog-to-digital converter (ADC) oversamples a sense resistor voltage an integer number of times within each period of the switching frequency. A control circuit sets the switching frequency of the driver during the steady-state operational mode by providing predetermined switching times. The control circuit disables switching during the transient mode. Dither can be applied during the steady-state mode.

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1. A frequency-controlled load driver circuit comprising:a solenoid load connected with a series sense resistor;a switching driver coupled to the load, the driver operable to switch a load current at a predetermined switching frequency during a steady-state operational mode;an analog-to-digital conv

1. A frequency-controlled load driver circuit comprising:a solenoid load connected with a series sense resistor;a switching driver coupled to the load, the driver operable to switch a load current at a predetermined switching frequency during a steady-state operational mode;an analog-to-digital converter (ADC) coupled to the sense resistor for oversampling a voltage thereacross, wherein the ADC oversamples the sense resistor voltage 2N times, where N is an integer, within each period of the predetermined switching frequency; anda control circuit coupled to the ADC and driver, the control circuit is operable to set the switching frequency of the driver during the steady-state operational mode by providing predetermined switching times, and the control circuit is also able to disable switching during a transient operational mode.2. The circuit of claim 1, wherein the control circuit is operable to apply a dither to the load current during steady-state conditions.3. The circuit of claim 2, wherein a frequency of the applied dither is different than the switching frequency and is applied to the load current by varying the switching frequency at a desired dither frequency.4. The circuit of claim 2, wherein the dither frequency is the same as the switching frequency.5. The circuit of claim 1, wherein the control circuit is operable to adjust a duty cycle of the switching driver to maintain a desired average of the load current.6. The circuit of claim 1, wherein the control circuit is operable to maintain the operating phase of the load driver circuit when switching between steady-state and transient modes.7. A frequency-controlled load driver circuit comprising:a solenoid load connected with a series sense resistor;a switching driver coupled to the load, the driver operable to switch a load current at a predetermined switching frequency during a steady-state operational mode;an analog-to-digital converter (ADC) coupled to the sense resistor for oversampling a voltage thereacross, wherein the ADC oversamples the sense resistor voltage 2N equally-spaced times, where N is an integer, and sums the samples within each period of the predetermined frequency; anda control circuit coupled to the ADC and driver, the control circuit is operable to set the switching frequency of the driver during the steady-state operational mode by providing predetermined switching times, and the control circuit is also operable to apply dither to the load current and to disable switching and dither during a transient operational mode.8. The circuit of claim 7, wherein the dither frequency is different than the switching frequency and is applied to the load current by varying the switching frequency at a desired dither frequency.9. The circuit of claim 7, wherein the control circuit is operable to adjust a duty cycle of the switching driver to maintain a desired average of the load current.10. The circuit of claim 7, wherein the control circuit is operable to maintain the operating phase of the load driver circuit when changing from the steady-state mode to the transient mode.11. The circuit of claim 7, wherein the control circuit is operable to change the load driver circuit from the steady-state mode to the transient mode by setting at least one new switching setpoint and disabling dither, and the control circuit is operable to switch from transient mode to steady-state mode when the load current is within a predetermined percentage of the new setpoint.12. The circuit of claim 11, wherein the control circuit is operable to maintain the operating phase of the load driver circuit when switching between transient and steady-state modes, wherein when the load driver circuit is being switched from transient mode to steady-state mode, the control circuit is operable to reinstate a dither frequency to the load current for resynchronization until a start of a next period, whereupon the switching frequency is also reinstated in phase with the control logic.13. A method for controlling a frequency-controlled load driver circuit, the method comprising the steps of:providing a solenoid load with a series switching driver and a series sense resistor and an analog-to-digital converter coupled thereto;setting the switching driver to operate at a predetermined switching frequency during a steady-state operational mode by determining appropriate switching times;oversampling a voltage across the sense resistor due to a load current of the solenoid by the analog-to-digital converter 2N of times, where N is an integer, within each period of the predetermined switching frequency;applying dither to the load current;changing to a transient operational mode by disabling switching of the switching driver; andchanging to a steady-state operational mode by enabling switching of the switching driver at predetermined switching times to set the switching frequency of the switching driver.14. The method of claim 13, wherein the applying step includes applying a frequency of the dither different than the switching frequency by varying the switching frequency at a desired dither frequency.15. The method of claim 13, further comprising the step of adjusting a duty cycle of the switching driver to maintain a desired average of the load current.16. The method of claim 13, wherein the changing steps include maintaining the operating phase of the load driver circuit when changing between the steady-state mode and the transient modes.17. The method of claim 13, wherein the changing to a transient operational mode includes disabling the dither.18. The method of claim 13, wherein the changing to a steady-state operational mode includes reinstating dither to the load current for resynchronization until a start of a next period, whereupon the switching frequency is also reinstated in phase with control logic.19. The method of claim 13, wherein the applying step includes applying a frequency of the dither the same as the switching frequency.