IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0846844
(2001-05-01)
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발명자
/ 주소 |
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출원인 / 주소 |
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대리인 / 주소 |
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인용정보 |
피인용 횟수 :
70 인용 특허 :
4 |
초록
▼
An amplifier, for use in regulator circuits and other applications, having dynamic input stage biasing includes an input stage operatively coupled to an input of the amplifier. A controlled current source coupled to the input stage is responsive to a control signal for at least partially controlling
An amplifier, for use in regulator circuits and other applications, having dynamic input stage biasing includes an input stage operatively coupled to an input of the amplifier. A controlled current source coupled to the input stage is responsive to a control signal for at least partially controlling an input bias current generated by the controlled current source. The amplifier further includes a sense circuit operatively connected in a feedback arrangement between an output of the amplifier and the controlled current source. The sense circuit measures an output load current from the amplifier and generates the control signal in response thereto, whereby the input bias current is a function of the output load current of the amplifier. In this manner, parasitic poles associated with the amplifier are pushed out in frequency so as to provide superior amplifier stability while dissipating low quiescent current, particularly at low output load current levels.
대표청구항
▼
An amplifier, for use in regulator circuits and other applications, having dynamic input stage biasing includes an input stage operatively coupled to an input of the amplifier. A controlled current source coupled to the input stage is responsive to a control signal for at least partially controlling
An amplifier, for use in regulator circuits and other applications, having dynamic input stage biasing includes an input stage operatively coupled to an input of the amplifier. A controlled current source coupled to the input stage is responsive to a control signal for at least partially controlling an input bias current generated by the controlled current source. The amplifier further includes a sense circuit operatively connected in a feedback arrangement between an output of the amplifier and the controlled current source. The sense circuit measures an output load current from the amplifier and generates the control signal in response thereto, whereby the input bias current is a function of the output load current of the amplifier. In this manner, parasitic poles associated with the amplifier are pushed out in frequency so as to provide superior amplifier stability while dissipating low quiescent current, particularly at low output load current levels. ransformer including a substantially hexahedral piezoelectric body having opposite upper and lower surfaces, a substantially rhombic input electrode formed in a central portion of each of said upper and lower surfaces of said piezoelectric body, and an output electrode formed on each of said upper and lower surfaces of said piezoelectric body, said output electrode surrounding the respective input electrode while being spaced from said input electrode at a regular interval; and a digital controller coupled to at least said inverter for modulating a switching frequency controlling a switching period of said inverter, when the lamp is turned on/off, to control an intensity of illumination of the lamp. 2. The electronic ballast as set forth in claim 1, wherein said high-power piezoelectric transformer is made of a composition expressed by the following chemical formula: Pb1-aSra[(Ni1/2W1/2)b(Mn1/3Nb2/3)c(Zr1-xTix)1-b-c]O3+kPbO. 3. The electronic ballast as set forth in claim 2, wherein, in said chemical formula, a is in a range of 0_0.06 mol, b is in a range of 0.01_0.05 mol, c is in a range of 0.01_0.09 mol, x is in a range of 0.47_0.53 mol and k is in a range of 0.1_0.7 wt %. 4. The electronic ballast as set forth in claim 1, wherein said high-power piezoelectric transformer operates at 66 KHz. 5. The electronic ballast as set forth in claim 1, further comprising: a lamp sensor for sensing an abnormal state of the lamp; and a current/voltage sensor for sensing the current and voltage supplied to the lamp; said digital controller being coupled to said lamp and current/voltage sensors and adapted to determine a variety of states of the lamp in response to external signals and output signals from said lamp sensor and current/voltage sensor, and modulate the switching frequency of said inverter according to the determined states to automatically control the intensity of illumination of the lamp. 6. A digitally controlled electronic ballast for turning on/off a lamp, said ballast comprising: a rectifier for rectifying an input low-frequency alternating current (AC) voltage to obtain a direct current (DC) voltage; a power factor improving circuit coupled to said rectifier for maintaining the DC voltage outputted from said rectifier at a constant level; an inverter coupled to said power factor improving circuit for performing a switching operation to convert a power factor-improved DC voltage received from said power factor improving circuit into a high-frequency AC voltage; a resonance circuit connected to an output of said inverter for supplying said high-frequency AC voltage from said inverter to the lamp, said resonance circuit including a coil and a high-power piezoelectric transformer coupled to said coil; and a digital controller coupled to at least said inverter for modulating a switching frequency controlling a switching period of said inverter, when the lamp is turned on/off, to control an intensity of illumination of the lamp; wherein said digital controller includes: a microcomputer for outputting an output signal and modulating the frequency of the output signal, when the lamp is turned on or off, according to a current state of the lamp; and a phase locked loop coupled to said microcomputer for performing a frequency multiplication operation on the output signal from said microcomputer and applying a signal of a frequency within a predetermined range to said inverter as a result of the frequency multiplication operation. 7. The electronic ballast as set forth in claim 6, wherein said high-power piezoelectric transformer is made of a composition expressed by the following chemical formula: Pb1-aSra[(Ni1/2W1/2)b(Mn1/3Nb2/3)c(Zr1-xTix)1-b-c]O 3+kPbO. 8. The electronic ballast as set forth in claim 7, wherein, in said chemical formula, a is in a range of 0_0.06 mol, b is in a range of 0.01_0.05 mol, c is in a range of 0.01_0.09 mol, x is in a range of 0.47_0.53 mol and k is in a range of 0.1_0.7 wt %. 9. The electronic ballast as set forth in claim 6, wherein said high-power piezoelectric transformer operates at 66 KHz. 10. The electronic ballast as set forth in claim 6, further comprising: a lamp sensor for sensing an abnormal state of the lamp; and a current/voltage sensor for sensing the current and voltage supplied to the lamp; said digital controller being coupled to said lamp and current/voltage sensors and adapted to determine a variety of states of the lamp in response to external signals and detected signals from said lamp sensor and current/voltage sensor, and modulate the switching frequency of said inverter according to the determined states to automatically control the intensity of illumination of the lamp. 11. A digitally controlled electronic ballast for turning oh/off a lamp, said ballast comprising: a rectifier for rectifying an input low-frequency alternating current (AC) voltage to obtain a direct current (DC) voltage; a power factor improving circuit coupled to said rectifier for maintaining the DC voltage outputted from said rectifier at a constant level; an inverter coupled to said power factor improving circuit for performing a switching operation to convert a power factor-improved DC voltage received from said power factor improving circuit into a high-frequency AC voltage; a resonance circuit connected to said inverter for supplying said high-frequency AC voltage from said inverter to the lamp, said resonance circuit including a coil and a high-power piezoelectric transformer coupled to said coil; and a digital controller electrically coupled to at least said inverter for modulating a switching frequency controlling a switching period of said inverter, when the lamp is turned on/off, to control an intensity of illumination of the lamp. 12. The electronic ballast as set forth in claim 11, wherein said piezoelectric transformer includes: a piezoelectric body having opposite upper and lower surfaces; an input electrode formed in a central portion of each of said upper and lower surfaces of said piezoelectric body; and an output electrode formed on each of said upper and lower surfaces of said piezoelectric body, said output electrode surrounding the respective input electrode while being spaced from said input electrode. 13. The electronic ballast as set forth in claim 12, wherein said high-power piezoelectric transformer is made of a composition expressed by the following chemical formula: Pb1-aSra[(Ni1/2W1/2)b(Mn1/3Nb2/3)c(Zr1-xTix)1-b-c]O3+kPbO. 14. The electronic ballast as set forth in claim 13, wherein, in said chemical formula, a is in a range of 0_0.06 mol, b is in a range of 0.01_0.05 mol, c is in a range of 0.01_0.09 mol, x is in a range of 0.47_0.53 mol and k is in a range of 0.1_0.7 wt %. 15. The electronic ballast as set forth in claim 12, further comprising: a lamp sensor coupled to one of the output electrodes of said piezoelectric transformer for sensing an abnormal state of the lamp; and a current/voltage sensor coupled to the other output electrode of said piezoelectric transformer for sensing the current and voltage supplied to the lamp; said digital controller being coupled to said lamp and current/voltage sensors and adapted to determine a variety of states of the lamp in response to external signals and detected signals from said lamp sensor and current/voltage sensor, and modulate the switching frequency of said inverter according to the determined states to automatically control the intensity of illumination of the lamp. 16. The electronic b allast as set forth in claim 12, wherein each of the output electrodes of said piezoelectric transformer completely encircles the respective input electrode. 17. The electronic ballast as set forth in claim 16, wherein the input electrodes of said piezoelectric transformer are coupled to output terminals of said resonance circuit for applying said high-frequency AC voltage to said piezoelectric body, and the output electrodes of said piezoelectric transformer are coupled to output terminals of said electronic ballast for connection to the lamp. ehicle; and a timer that measures the length of discharge time having elapsed since a battery discharge start, wherein; said control device implements control so as to start a battery discharge if said acceleration detection device detects that the acceleration of the vehicle has been lowered to a value equal to or less than 0 and implements control so as to start a battery charge by halting the battery discharge and storing the power generated at said generator when the discharge time measured by said timer matches a predetermined length of time. 6. A vehicle battery charge control apparatus according to claim 5, further comprising; a vehicle speed detection device that detects vehicle speed, wherein; said.acceleration detection device ascertains the acceleration of the vehicle based upon the vehicle speed detected by said vehicle speed detection device. 7. A vehicle battery charge control apparatus comprising; a power generation means for generating power by converting regenerative energy manifesting when the vehicle is decelerating to power; a control means for controlling charge/discharge of the battery; an acceleration detection means for detecting acceleration of the vehicle; and a time count means for measuring the length of discharge time having elapsed since a battery discharge start, wherein; said control means implements control so as to start a battery discharge if said acceleration detection means detects that the acceleration of the vehicle has been reduced to a value equal to or less than 0 and implements control so as to start a battery charge by halting the battery discharge and storing the power generated at said power generation means when the discharge time measured by said time count means matches a predetermined length of time. 8. A method of vehicle battery charge control comprising; detecting an acceleration of the vehicle; starting a battery discharge if the detected acceleration is determined to have been reduced to a value equal to or less than 0; and starting a battery charge by halting the battery discharge and using regenerative power when the length of time having elapsed since the battery discharge start matches a predetermined length of time.
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