High precision DC-DC converter
First Claim
1. A high precision DC-DC converter circuit for converting a direct current (DC) input voltage VDD to a DC output voltage VCC having a first accuracy level, the circuit comprising:
- a switching transistor coupled to VDD, the switching transistor including an input and a first output;
a switching regulator circuit coupled to the input of the switching transistor for driving the switching transistor on and off according to a sensed voltage level such that VDD is coupled to the first output when the switching transistor is on, wherein the switching regulator circuit compares the sensed voltage level to a first setpoint reference voltage level having a second accuracy level to determine a duty cycle for driving the switching transistor;
an output circuit coupled to the first output, the output circuit including a second output, the output circuit for generating a first voltage level at the second output in response to VDD being coupled and uncoupled from the first output; and
an output voltage regulator circuit coupled to the second output and the switching regulator circuit, the output voltage regulator circuit for causing the switching regulator circuit to vary the duty cycle by controlling the sensed voltage such that the first voltage level is equal to VCC at the first accuracy level, the output voltage regulator for generating the sensed voltage level in response to comparing the first voltage level to a second internal setpoint reference voltage level having a third accuracy level that is more precise than the first and second accuracy levels.
1 Assignment
0 Petitions
Accused Products
Abstract
A high precision DC-DC converter circuit having improved efficiency is disclosed. The DC-DC converter circuit includes a low accuracy switching regulator circuit for driving a switching field effect transistor (FET) on and off. A high accuracy output voltage regulator circuit is inserted into the feedback loop between the output of the DC-DC converter circuit and the sensing input of the switching regulator circuit such that the accuracy of the output voltage regulator circuit primarily determines the precision of the DC-DC converter. The DC-DC converter also includes a quick shut-off circuit coupled to the gate and source of the FET for driving the gate of the FET negative when the FET is switched off such that switching losses are minimized. A second embodiment of the high precision DC-DC converter is used to convert from 5.0 to 3.3 volts. The second embodiment includes a transformer, one winding of which is used as an output inductor. The second winding is used as part of a multiplying bootstrap circuit that approximately triples the 5.0 volt input voltage to drive the gate of an n-channel switching FET. The second embodiment also includes a circuit for extending the duty cycle of the switching regulator in response to a load transient on the output.
-
Citations
35 Claims
-
1. A high precision DC-DC converter circuit for converting a direct current (DC) input voltage VDD to a DC output voltage VCC having a first accuracy level, the circuit comprising:
-
a switching transistor coupled to VDD, the switching transistor including an input and a first output; a switching regulator circuit coupled to the input of the switching transistor for driving the switching transistor on and off according to a sensed voltage level such that VDD is coupled to the first output when the switching transistor is on, wherein the switching regulator circuit compares the sensed voltage level to a first setpoint reference voltage level having a second accuracy level to determine a duty cycle for driving the switching transistor; an output circuit coupled to the first output, the output circuit including a second output, the output circuit for generating a first voltage level at the second output in response to VDD being coupled and uncoupled from the first output; and an output voltage regulator circuit coupled to the second output and the switching regulator circuit, the output voltage regulator circuit for causing the switching regulator circuit to vary the duty cycle by controlling the sensed voltage such that the first voltage level is equal to VCC at the first accuracy level, the output voltage regulator for generating the sensed voltage level in response to comparing the first voltage level to a second internal setpoint reference voltage level having a third accuracy level that is more precise than the first and second accuracy levels. - View Dependent Claims (2, 3)
-
-
4. A high precision DC-DC converter circuit for converting a direct current (DC) input voltage VDD to a DC output voltage VCC having a first accuracy level, the circuit comprising:
-
a switching transistor coupled to VDD, the switching transistor including an input and a first output; a switching regulator circuit coupled to the input of the switching transistor for driving the switching transistor on and off according to a sensed voltage level such that VDD is coupled to the first output when the switching transistor is on, wherein the switching regulator circuit compares the sensed voltage level to a first setpoint reference voltage level having a second accuracy level to determine a duty cycle for driving the switching transistor, the switching regulator circuit further including; a switching regulator coupled to the sensed voltage level and including a third output, the switching regulator for generating a plurality of pulses having a second voltage level on the third output; and a bootstrap circuit coupled to the third output and to the input, the bootstrap circuit for pulling up the second voltage level such that the switching transistor operates in a saturation range when switched on; an output circuit coupled to the first output, the output circuit including a second output, the output circuit for generating a first voltage level at the second output in response to VDD being coupled and uncoupled from the first output, the output circuit further including a transformer having a primary winding and a secondary winding, the primary and secondary windings being coupled to the first output, the secondary winding being coupled to the bootstrap circuit; and an output voltage regulator circuit coupled to the second output and the switching regulator circuit, the output voltage regulator circuit for causing the switching regulator circuit to vary the duty cycle by controlling the sensed voltage such that the first voltage level is equal to VCC at the first accuracy level, the output voltage regulator for generating the sensed voltage level in response to comparing the first voltage level to a second internal setpoint reference voltage level having a third accuracy level that is more precise than the first and second accuracy levels. - View Dependent Claims (5, 6, 7, 8)
-
-
9. A computer system comprising:
-
a power supply for outputting a nominal direct current (DC) voltage VDD at a first accuracy level; a plurality of components coupled to the power supply, each of the components using a system operating voltage SVCC as its operating voltage; a processor coupled to at least one of the plurality of components, the processor requiring a DC voltage of VCC at a second accuracy level as its operating voltage; and a high precision DC-DC converter circuit coupled to the power supply and the processor, the DC-DC converter circuit for converting the DC voltage VDD to the DC voltage VCC at the second accuracy level, the DC-DC converter circuit further including; a switching transistor coupled to VDD, the switching transistor including an input and a first output; a switching regulator circuit coupled to the input of the switching transistor for driving the switching transistor on and off according to a sensed voltage level such that VDD is coupled to the first output when the switching transistor is on, wherein the switching regulator circuit compares the sensed voltage level to a first setpoint reference voltage level having a second accuracy level to determine a duty cycle for driving the switching transistor; an output circuit coupled to the first output, the output circuit including a second output, the output circuit for generating a first voltage level at the second output in response to VDD being coupled and uncoupled from the first output; and an output voltage regulator circuit coupled to the second output and the switching regulator circuit, the output voltage regulator circuit for causing the switching regulator circuit to vary the duty cycle by controlling the sensed voltage such that the first voltage level is equal to VCC at the first accuracy level, the output voltage regulator for generating the sensed voltage level in response to comparing the first voltage level to a second internal setpoint reference voltage level having a third accuracy level that is more precise than the first and second accuracy levels. - View Dependent Claims (10, 11, 12)
-
-
13. A computer system comprising:
-
a power supply for outputting a nominal direct current (DC) voltage VDD at a first accuracy level; a plurality of components coupled to the power supply, each of the components using a system operating voltage SVCC as its operating voltage; a processor coupled to at least one of the plurality of components, the processor requiring a DC voltage of VCC at a second accuracy level as its operating voltage; and a high precision DC-DC converter circuit coupled to the power supply and the processor, the DC-DC converter circuit for converting the DC voltage VDD to the DC voltage VCC at the second accuracy level, the DC-DC converter circuit further including; a switching transistor coupled to VDD, the switching transistor including an input and a first output; a switching regulator circuit coupled to the input of the switching transistor for driving the switching transistor on and off according to a sensed voltage level such that VDD is coupled to the first output when the switching transistor is on, wherein the switching regulator circuit compares the sensed voltage level to a first setpoint reference voltage level having a second accuracy level to determine a duty cycle for driving the switching transistor, the switching regulator circuit further including; a switching regulator coupled to the sensed voltage level and including a third output, the switching regulator for generating a plurality of having a second voltage level on the third output; and a bootstrap circuit coupled to the third output and to the input, the bootstrap circuit for pulling up the second voltage level such that the switching transistor operates in a saturation range when switched on; an output circuit coupled to the first output, the output circuit including a second output, the output circuit for generating a first voltage level at the second output in response to VDD being coupled and uncoupled from the first output, the output circuit further including a transformer having a primary winding and a secondary winding, the primary and secondary windings being coupled to the first output, the secondary winding being coupled to the bootstrap circuit; and an output voltage regulator circuit coupled to the second output and the switching regulator circuit, the output voltage regulator circuit fox causing the switching regulator circuit to vary the duty cycle by controlling the sensed voltage such that the first voltage level is equal to VCC at the first accuracy level, the output voltage regulator for generating the sensed voltage level in response to comparing the first voltage level to a second internal setpoint reference voltage level having a third accuracy level that is more precise than the first and second accuracy levels. - View Dependent Claims (14, 15, 16, 17)
-
-
18. A method for converting a direct current (DC) input voltage VDD into a DC output voltage VCC having a first accuracy level, the method comprising the steps of:
-
providing a switching transistor; switching the switching transistor on and off to produce an output voltage level equal to VDD multiplied by a duty cycle, the duty cycle being a percentage of time that the switching transistor is turned on; varying the duty cycle of the switching transistor in response to a comparison of a sensed voltage level to a first setpoint reference voltage having a second accuracy level; sensing the output voltage level; and generating the sensed voltage level in response to a comparison of the output voltage level to a second setpoint reference voltage having a third accuracy level that is more precise than the first and second accuracy levels such that the output voltage level is VCC within the first accuracy level. - View Dependent Claims (19, 20)
-
-
21. A method for converting a direct current (DC) input voltage VDD into a DC output voltage VCC having a first accuracy level, the method comprising the steps of:
-
providing a switching transistor; switching the switching transistor on and off to produce an output voltage level equal to VDD multiplied by a duty cycle, the duty cycle being a percentage of time that the switching transistor is turned on; varying the duty cycle of the switching transistor in response to a comparison of a sensed voltage level to a first setpoint reference voltage having a second accuracy level; sensing the output voltage level; generating the sensed voltage level in response to a comparison of the output voltage level to a second setpoint reference voltage having a third accuracy level that is more precise than the first and second accuracy levels such that the output voltage level is VCC within the first accuracy level; and extending the duty cycle of the switching transistor beyond a predetermined maximum duty cycle if a load increases such that extension of the duty cycle is necessary to provide sufficient power. - View Dependent Claims (22, 23)
-
-
24. A high precision DC-DC converter circuit for converting a direct current (DC) input voltage VDD to a DC output voltage VCC having a first accuracy level, the circuit comprising:
-
a switching transistor; means for switching the switching transistor on and off to produce an output voltage level equal to VDD multiplied by a duty cycle, the duty cycle being a percentage of time that the switching transistor is turned on; means for varying the duty cycle of the switching transistor in response to a comparison of a sensed voltage level to a first setpoint reference voltage having a second accuracy level; means for sensing the output voltage level; and means for generating the sensed voltage level in response to a comparison of the output voltage level to a second setpoint reference voltage having a third accuracy level that is more precise than the first and second accuracy levels such that the output voltage level is VCC within the first accuracy level. - View Dependent Claims (25, 26)
-
-
27. A high precision DC-DC converter circuit for converting a direct current (DC) input voltage VDD to a DC output voltage VCC having a first accuracy level, the circuit comprising:
- ;
a switching transistor; means for switching the switching transistor on and off to produce an output voltage level equal to VDD multiplied by a duty cycle, the duty cycle being a percentage of time that the switching transistor is turned on; means for varying the duty cycle of the switching transistor in response to a comparison of a sensed voltage level to a first setpoint reference voltage having a second accuracy level; means for sensing the output voltage level; means for generating the sensed voltage level in response to a comparison of the output voltage level to a second setpoint reference voltage having a third accuracy level that is more precise than the first and second accuracy levels such that the output voltage level is VCC within the first accuracy level; and means for extending the duty cycle of the switching transistor beyond a predetermined maximum duty cycle if a load increases such that extension of the duty cycle is necessary to provide sufficient power. - View Dependent Claims (28, 29)
- ;
-
30. A computer system comprising:
-
a power supply for outputting a nominal direct current (DC) voltage VDD at a first accuracy level; an integrated circuit coupled to at least one of the plurality of components, the integrated circuit requiring a DC voltage of VCC at a second accuracy level as its operating voltage; and a high precision DC-DC converter circuit coupled to the power supply and the integrated circuit, the DC-DC converter circuit for converting the DC voltage VDD to the DC voltage VCC at the second accuracy level, the DC-DC converter circuit further including; a switching transistor; means for switching the switching transistor on and off to produce an output voltage level equal to VDD multiplied by a duty cycle, the duty cycle being a percentage of time that the switching transistor is turned on; means for varying the duty cycle of the switching transistor in response to a comparison of a sensed voltage level to a first setpoint reference voltage having a second accuracy level; means for sensing the output voltage level; and means for generating the sensed voltage level in response to a comparison of the output voltage level to a second setpoint reference voltage having a third accuracy level that is more precise than the first and second accuracy levels such that the output voltage level is VCC within the first accuracy level. - View Dependent Claims (31, 32)
-
-
33. A computer system comprising:
-
a power supply for outputting a nominal direct current (DC) voltage VDD at a first accuracy level; an integrated circuit coupled to at least one of the plurality of components, the integrated circuit requiring a DC voltage of VCC at a second accuracy level as its operating voltage; and a high precision DC-DC converter circuit coupled to the power supply and the integrated circuit, the DC-DC converter circuit for converting the DC voltage VDD to the DC voltage VCC at the second accuracy level, the DC-DC converter circuit further including; a switching transistor; means for switching the switching transistor on and off to produce an output voltage level equal to VDD multiplied by a duty cycle, the duty cycle being a percentage of time that the switching transistor is turned on; means for varying the duty cycle of the switching transistor in response to a comparison of a sensed voltage level to a first setpoint reference voltage having a second accuracy level; means for sensing the output voltage level; means for generating the sensed voltage level in response to a comparison of the output voltage level to a second setpoint reference voltage having a third accuracy level that is more precise than the first and second accuracy levels such that the output voltage level is VCC within the first accuracy level; and means for extending the duty cycle of the switching transistor beyond a predetermined maximum duty cycle if a load increases such that extension of the duty cycle is necessary to provide sufficient power. - View Dependent Claims (34, 35)
-
Specification