|Publication number||USRE40843 E1|
|Application number||US 11/262,564|
|Publication date||Jul 14, 2009|
|Filing date||Oct 28, 2005|
|Priority date||Mar 22, 2001|
|Also published as||CA2442083A1, CA2442083C, CN1505776A, CN100392545C, DE60225425D1, DE60225425T2, EP1370917A1, EP1370917A4, EP1370917B1, US6639369, US20020153849, WO2002077739A1|
|Publication number||11262564, 262564, US RE40843 E1, US RE40843E1, US-E1-RE40843, USRE40843 E1, USRE40843E1|
|Inventors||Thomas J. Ribarich|
|Original Assignee||International Rectifier Corporation|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (29), Non-Patent Citations (1), Referenced by (4), Classifications (17), Legal Events (2)|
|External Links: USPTO, USPTO Assignment, Espacenet|
The present application claims the benefit and priority of U.S. Provisional Application Ser. No. 60/277,636 filed Mar. 22, 2001 and entitled “DIMMABLE HID BALLAST CONTROL CIRCUIT”, the entire disclosure of which is incorporated by reference herein.
The present invention relates to a dimmable ballast for a high intensity discharge (HID) lamp, for example, a metal halide HID lamp. The design of electronic ballasts for HID lamps needs to take into consideration that HID lamps have different characteristics than other gas discharge lamps, e.g., fluorescent lamps. In particular, HID lamps have higher ignition voltages, typically 3 Kv peak to peak. Fluorescent lamps have ignition voltages of typically 1 Kv peak to peak. HID lamps have no filaments, so there is no need to preheat filaments. Electronic ballasted fluorescent lamps are typically operated at 30-50 kHz. HID lamps have been operated at these frequencies also, but acoustic resonance often occurs which can cause damage to the lamp due to arcing and often even cause the lamp to explode. As a result, HID lamps are typically operated at lower frequencies in the few 100 Hz range to avoid acoustic resonance. At these low frequencies larger full bridge switching circuits are employed to drive the HID lamp with a square wave without resonant output circuits.
In addition, HID lamps in the prior art are typically ignited with a single pulse starter, leading to reliability problems, as the lamps may fail to strike with such single pulse igniters. Further, when HID lamps are hot, the ignition voltage rises to much higher levels, for example, on the order of 25 kilovolts or so.
These characteristics require that the ballasts for such HID lamps have different characteristics than the ballasts for typical fluorescent lamps. In addition, HID lamps have typically only two connections whereas fluorescent lamps typically have four connections with two of the connections being for the lamp filament. An example of a dimming ballast for a fluorescent lamp is shown in U.S. Pat. No. 6,008,593 assigned to the assignee of the present application.
The invention relates to a fully functional dimming ballast for an HID lamp, for example a metal halide HID lamp. The design includes an EMI filter, a rectifier, an active power factor control stage, ballast output stage, ballast control stage and additional timing circuitry for multiple ignitions. The ballast control stage is used to regulate lamp power, set the minimum and maximum brightness levels and protect the ballast against conditions such as lamp strike failures, low DC bus level, thermal overload or lamp failure during normal operation. When compared to conventional HID ballasts, the present invention has advantages in that it allows dimming and thus energy savings, higher reliability because a single pulse igniter is not used or required, high efficiency (increased lumens/watt), easy adaptability to different lamp types and is lower in weight and size and cost. In addition, because the lamp is operated at high frequencies above 50 kHz, and preferable above 100 kHz, acoustic resonance is not a problem and component size is reduced.
According to one aspect, the invention comprises a dimmable electronic ballast for an HID lamp comprising: a rectifier stage for rectifying an AC input and providing a rectified DC output, a power factor correction stage for modifying a power factor of said AC input and for providing an increased voltage DC output from said rectified DC output, an electronic ballast control circuit for providing a driving signal comprising a pulse train for controlling a switching operation of an output switch stage driving the HID lamp; said output switch stage comprising at least one electronic switching element coupled to said increased voltage DC output for providing a pulsed power signal to the HID lamp to power the lamp, said electronic ballast control circuit having a feedback input comprising a signal related to the power dissipated by said HID lamp for maintaining said power at a desired level, the desired level being set by a dimming control input to said electronic ballast control circuit.
Preferably, a multiple pulse ignition timing circuit is provided for more reliable lamp ignition.
According to another aspect, the invention comprises a dimmable electronic ballast for an HID lamp comprising, a rectifier stage for rectifying an AC input and providing a rectified DC output, a boost stage for providing an increased voltage DC output from said rectified DC output, an electronic ballast control circuit for providing a driving signal comprising a pulse train for controlling a switching operation of an output switch stage driving the HID lamp; and said output switch stage comprising at least one electronic switching element coupled to said increased voltage DC output for providing a pulsed power signal to the HID lamp to power the lamp, said electronic ballast control circuit having a feedback input comprising a signal related to a phase angle of one of the voltage across said HID lamp and a phase angle of the current through the HID lamp for maintaining the power dissipated by said HID lamp at a desired level, the desired level being set by a dimming control input to said electronic ballast control circuit.
Other features and advantages of the present invention will become apparent from the following detailed description.
The invention will now be described in the following detailed description with reference to the drawings in which:
With reference now to the drawings,
The DC bus voltage is fed to an output switch stage 40 which includes at least one electronic switch which switches the DC bus voltage across the lamp 50, through a resonant LC circuit including a resonant inductance 60, resonant capacitance 62 and series isolating capacitance 64. The LC circuit shapes the pulse width modulated output from the output stage into an approximate sinusoidal signal for driving the lamp 50. Voltage peak levels across the lamp are approximately 1 Kv. The operating frequency is high, above 50 kHz, and preferably above 100 kHz. The high frequency appears to eliminate the acoustic resonance that occurs in prior art circuits operating at lower frequencies in the 25 to 40 kHz range. The lamp 50 may be a metal halide HID lamp, for example a 250 watt metal halide HID lamp. Although a circuit diagram will be shown in
Output stage 40 is controlled by a ballast control circuit 80. The ballast control circuit provides pulse width modulated driver signals to the output stage 40 to control the switching operation of the output stage. The ballast control circuit 80 includes a dimming input 82 and receives another input from an ignition timing circuit 90. The purpose of the ignition timing circuit 90 is to modulate and control the lamp power pulses applied to the lamp during ignition, and in the event that the lamp does not ignite, to provide a waiting period to allow the lamp to cool down before ignition pulses are again provided to start the lamp. As discussed, hot HID lamps will not restrike at cold lamp ignition voltage levels. The timer circuit 90 provides multiple ignition pulses separated by a wait period. By waiting until the lamp has cooled, the need for producing very high hot restrike voltages has been eliminated. Also, because multiple ignition pulses are provided, greater reliability in striking is achieved, and the lamp will strike more reliably at lower voltages around 1 Kv.
The overall design shown in
The operation of the power factor correction stage and boost converter will not be described in detail herein as such power factor correction stages and boost converters are well known to those of skill in the art. The purpose of the power factor correction stage 20 is to boost the DC bus voltage and suitably shape the waveform so that a high AC input power factor is achieved, typically a power factor of 0.99 and, in this case, 0.99 voltage leading, since the electronic ballast for the HID lamp is slightly inductive.
The DC bus voltage (typically approximately 400V) across the rails 24 and 22 is provided to an output switch stage 40 comprising two electronic switching elements M1 and M2 arranged in a half bridge configuration, as well known to those of skill in the art. A current sense resistor RCS2 is provided in series with the electronic switching elements M1 and M2, which may be a pair of MOSFETS. The output of the output switch stage is provided at the common connection point of the two switching transistors M1 and M2 which is the voltage VS, to be described later with reference to the voltage waveforms. The voltage VS comprises a pulse width modulated pulse train which is fed through an LC circuit to the lamp 50. The LC circuit includes a resonant inductance LRES and resonant capacitance comprising a resonant capacitance CRES shown in
The ballast control stage 80 includes a ballast control integrated circuit 84 which may be an IR2159 type device. The control IC 84 includes pins for providing various inputs as well known to those of skill in the art, including pins 1 and 2 labeled VDC and VCO. Pin VCO is coupled to capacitive and resistive components for controlling the oscillation frequency of the voltage controlled oscillator (VCO) in the integrated circuit 84 for controlling the output frequency. Pin VDC operates as line input voltage detection and is coupled through resistor RVDC1 to the rectified DC at rail 21. It is internally connected to under voltage/fault detection circuitry in IC84. Pin DIM is coupled through a resistor RDIM to a dimming input 82 which, in the embodiment described, comprises a variable DC supply for controlling the level of dimming. In particular, the dimming supply varies between 0.5 volts to 5 volts DC to provide the dimming range.
Pins MAX and MIN control the maximum and minimum lamp power settings, respectively, as determined by resistors RMAX and RMIN. Pin FMIN controls the minimum frequency setting as is determined by a resistor RFMIN. The various capacitive and resistive circuit components described are connected to the signal common which is coupled to the DC bus negative rail 22. The inputs for preheat are not necessary for HID lamps, as HID lamps have no filament and thus no preheat requirement. These inputs are appropriately tied low by suitable resistive/capacitive components.
Additional inputs and outputs of the control IC 84 include the high HO and low LO side outputs driving the electronic switching elements M1 and M2, respectively, the floating return VS coupled to the output of the output switch stage 40, and the high side gate driver floating supply VB. VCC comprises the voltage supply for the integrated circuit 84, and COM comprises the integrated circuit power and signal ground. A current sensing input CS to be described in greater detail below and a shut down input SD, also to be described in greater detail below, are also provided.
The electronic ballast control circuit 80, in known fashion, provides outputs at pins HO and LO to drive the electronic switches M1 and M2 alternatingly to provide power signal VS to the lamp resonant circuit.
In accordance with the present invention, the ballast control circuit 80 provides phase control dimming based upon dimming input 82. The current sensing resistor RCS2 in series with the electronic switches M1 and M2 of the output switch stage 40 provides a current sense signal through a resistor RLIM to the current sense input CS of the integrated circuit 84.
The integrated circuit 84 operates to sense the zero crossing of the signal CS. The zero crossing is proportional to the phase angle of the lamp current. As shown in
As discussed, the integrated circuit 84 operates by sensing the location of the CS zero crossing. This provides a closed loop feedback control to maintain the lamp brightness at the desired dimming level as set by the dimming input 82. As the zero crossing of voltage CS varies, the control 80 will vary the frequency of the HO and LO drive outputs and thus vary the frequency of the waveform ES provided to drive lamp 50. In particular, IC 84 operates such that the dimming control 82 provides a DC voltage which sets a phase reference. A phase detector in IC 84 comprises the reference phase and the phase of the output stage current as determined by the zero crossing of voltage CS, and produces an error signal proportional to the difference. The difference signal forces a VCO of IC 84 to steer the output frequency in the proper direction (increase frequency to dim, decrease frequency to brighten). The error is forced to zero, thus attaining and maintaining the desired brightness set by control 82. Further details of operation of IC84 can be found in the International Rectifier Preliminary Data Sheet No. PD60169D-IR2159(S) Dimming Ballast Control IC. The IC84 thus achieves phase control dimming of the HID lamp. The greater the phase angle, the less the real power delivered to the lamp, and thus the brightness is decreased. Conversely, the smaller the phase angle, the greater the real power delivered to the lamp and the higher the brightness level.
As discussed above, HID lamps will typically not restart when they are hot. Accordingly, to address this problem and also to increase starting reliability, a timing circuit 90 has been provided which comprises a binary counter integrated circuit 92 whose selected bit outputs are coupled through diodes DQ0 and DQ5-DQ10 to a common output 94 which is coupled through a resistor RSD1 to the pin SD (shut down) of the controller IC84. The purpose of the circuit 90 is to provide a series of pulses, shown in
In a preferred implementation, the SD pin is burst pulsed at approximately 1 second intervals before going into the steady shutdown mode as shown at 121 in FIG. 4. The steady shutdown mode may comprise a time period of, for example, 300 seconds. In addition, a normal ballast operating frequency i.e., the output voltage frequency applied to the lamp, may be approximately 120 kilohertz. During the ignition pulsing shown in
As shown in
Also provided is a reset circuit comprising transistor M5. Transistor M5 may be a PMOS FET. Its gate is coupled to VCC. Its source is connected to the voltage supply VDD for the counter integrated circuit 92. This voltage source VDD is connected through a resistor RVDD to the DC bus rail 24. The voltage VDD is clamped by zener diode DVDD to a preset voltage less than the voltage VCC. Accordingly, at startup, as voltage VCC rises and as is still below VDD, the MOSFET M5 will be on, providing a voltage level across resistor RRST, thereby providing a voltage input to reset pin 12 of integrated circuit 92, holding the counter IC 92 in a reset mode. As soon as VCC rises above voltage VDD, MOSFET M5 goes off and the reset level on pin 12 of integrated circuit 92 goes to zero, thus enabling the counter to begin counting and providing pulses on line 94. The purpose of the reset transistor M5 is to ensure that the counter IC 92 starts in a defined manner when the ballast is turned on. This will prevent the counter IC 92 from being in the wait mode 121 as shown in
A listing of circuit components and values can be found in the provisional application upon which priority is claimed.
The present invention accordingly achieves a high AC line power factor correction and provides efficiency in providing power to an HID lamp. In addition, it avoids acoustic resonance problems by operating at high frequencies, above 50 kHz and preferably above 100 kHz. The use of high frequencies also allows for a more compact half-bridge switching output stage and reduces the size of the resonant output stage. Thus, the invention uses a different approach than the prior art, which typically used low frequencies (about a few 100 Hz) to power HID lamps, in order to avoid acoustic resonance problems. The invention avoids these problems by using high frequencies (above 50 kHz and preferably above 100 kHz) instead.
Although the present invention has been described in relation to particular embodiments thereof, many other variations and modifications and other uses will become apparent to those skilled in the art. Therefore, the present invention should be limited not by the specific disclosure herein, but only by the appended claims.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US5010279||Mar 11, 1988||Apr 23, 1991||Lathom Michael S||Switched capacitive ballasts for discharge lamps|
|US5198726||Sep 30, 1991||Mar 30, 1993||U.S. Philips Corporation||Electronic ballast circuit with lamp dimming control|
|US5363020 *||Feb 5, 1993||Nov 8, 1994||Systems And Service International, Inc.||Electronic power controller|
|US5365152||Aug 18, 1992||Nov 15, 1994||Matsushita Electric Industrial Co. Ltd.||Apparatus for controlling the power to a discharge-lamp|
|US5381077 *||Dec 20, 1993||Jan 10, 1995||Mcguire; Thomas B.||Power control circuit for high intensity discharge lamps|
|US5416387||Nov 24, 1993||May 16, 1995||California Institute Of Technology||Single stage, high power factor, gas discharge lamp ballast|
|US5422546||Jul 8, 1993||Jun 6, 1995||Nilssen; Ole K.||Dimmable parallel-resonant electric ballast|
|US5428267||Jul 9, 1992||Jun 27, 1995||Premier Power Systems, Inc.||Regulated DC power supply|
|US5604411 *||Mar 31, 1995||Feb 18, 1997||Philips Electronics North America Corporation||Electronic ballast having a triac dimming filter with preconditioner offset control|
|US5623188||Jun 14, 1995||Apr 22, 1997||Sgs-Thomson Microelectronics S.A.||Method and apparatus for controlling an oscillating circuit of a low pressure fluorescent lamp|
|US5691605||Aug 9, 1995||Nov 25, 1997||Philips Electronics North America||Electronic ballast with interface circuitry for multiple dimming inputs|
|US5850127||May 10, 1996||Dec 15, 1998||Philips Electronics North America Corporation||EBL having a feedback circuit and a method for ensuring low temperature lamp operation at low dimming levels|
|US5903110||Jul 7, 1997||May 11, 1999||U.S. Philips Corporation||Igniting circuit operated by varying the impedance value of the controller|
|US5914566||Jan 6, 1997||Jun 22, 1999||Koito Manufacturing Co., Ltd.||Lighting circuit for applying a negative AC voltage to a discharge lamp|
|US5959410||Jan 29, 1997||Sep 28, 1999||Matsushita Electric Works R&D Laboratory, Inc.||Charge pump power factor correction circuit for power supply for gas discharge lamp|
|US6028399||Jun 23, 1998||Feb 22, 2000||Electro-Mag International, Inc.||Ballast circuit with a capacitive and inductive feedback path|
|US6034489 *||Dec 4, 1997||Mar 7, 2000||Matsushita Electric Works R&D Laboratory, Inc.||Electronic ballast circuit|
|US6057652||Feb 9, 1996||May 2, 2000||Matsushita Electric Works, Ltd.||Power supply for supplying AC output power|
|US6075326||Apr 20, 1998||Jun 13, 2000||Nostwick; Allan A.||High intensity discharge lamp ballast and lighting system|
|US6094017||Sep 30, 1998||Jul 25, 2000||Power Circuit Innovations, Inc.||Dimming ballast and drive method for a metal halide lamp using a frequency controlled loosely coupled transformer|
|US6100645||Dec 18, 1998||Aug 8, 2000||Electro-Mag International, Inc.||Ballast having a reactive feedback circuit|
|US6107754 *||Jun 23, 1999||Aug 22, 2000||Inlight Co., Ltd.||Electronic ballast for high-intensity discharge lamp and method of driving high-intensity discharge lamp|
|US6111368||Sep 26, 1997||Aug 29, 2000||Lutron Electronics Co., Inc.||System for preventing oscillations in a fluorescent lamp ballast|
|US6259215 *||Aug 20, 1998||Jul 10, 2001||Romlight International, Inc.||Electronic high intensity discharge ballast|
|US6285138||Dec 3, 1999||Sep 4, 2001||Matsushita Electric Industrial Co., Ltd.||Apparatus for lighting fluorescent lamp|
|US6313587||Nov 5, 1999||Nov 6, 2001||Fusion Lighting, Inc.||High frequency inductive lamp and power oscillator|
|US6486616 *||Feb 25, 2000||Nov 26, 2002||Osram Sylvania Inc.||Dual control dimming ballast|
|US6639369 *||Mar 21, 2002||Oct 28, 2003||International Rectifier Corporation||Electronic dimmable ballast for high intensity discharge lamp|
|US20020030456||Feb 9, 2001||Mar 14, 2002||Fairchild Korea Semiconductor, Ltd.||Lamp system with electronic ballast|
|1||Adams, J. et al., "A new control IC for dimmable high-frequency electronic ballasts", Applied power Electronics Conference and Exposition, 1999, APEC 1999. Fourteenth Annual Dallas, TxX USA Mar. 14-18, 1999, Piscataway, NJ, USA, IEEE, US, Mar. 14, 1999, pp. 713-719.|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US7750583 *||Mar 22, 2006||Jul 6, 2010||Osram Gesellschaft Mit Beschraenkter Haftung||Electronic reactive current oscillation-reducing ballast|
|US8773037||Dec 27, 2010||Jul 8, 2014||Empower Electronics, Inc.||Ballast configured to compensate for lamp characteristic changes|
|US20090206774 *||Mar 22, 2006||Aug 20, 2009||Patent-Treuhand-Gesellschaft Fur Elektrische Gluhlampen Mbh||Electronic reactive current oscillation-reducing ballast|
|US20110187287 *||Dec 27, 2010||Aug 4, 2011||Empower Electronics, Inc.||Ballast configured to compensate for lamp characteristic changes|
|U.S. Classification||315/307, 315/291|
|International Classification||H05B41/292, H05B41/288, H05B41/392, G05F1/00, H02M3/155, H05B41/24|
|Cooperative Classification||Y02B20/202, H05B41/2925, H05B41/2883, H05B41/3928, H05B41/2887|
|European Classification||H05B41/292C4, H05B41/288K4, H05B41/392D8H, H05B41/288E2B|
|Apr 28, 2011||FPAY||Fee payment|
Year of fee payment: 8
|Apr 28, 2015||FPAY||Fee payment|
Year of fee payment: 12