JPS61269898A - Power source unit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a switching type stabilized power supply device that supplies power to a load, and more particularly to a discharge lamp lighting device whose load is a discharge lamp.

Conventional technology In recent years, stable power supplies for electronic devices and discharge lamps have been required to be compact, lightweight, highly efficient, and inexpensive.
Switching type stabilized power supplies using semiconductor elements are increasingly being adopted.

In this type of power supply, a controlled semiconductor switch such as a transistor or a thyristor is generally turned on and off at a high frequency according to predetermined conditions to control a load as a switching element. At that time, the output voltage to the load is generally controlled to be constant.

Furthermore, when the load is a discharge lamp, particularly a saturated vapor pressure type discharge lamp such as a high-pressure sodium lamp, the load characteristics vary greatly depending on the supply voltage, so the output voltage of the power supply must be kept constant. Therefore, in conventional stabilized power supplies and discharge lamp lighting devices, for example, RCA APPLICA
TION NOTE) AN-3616P, 5, as shown in FIG. In FIG. 2, 1 is a DC power supply, 2 is a transistor, 3 is an inductance, 4 is a discharge lamp, 6 is a capacitor connected in parallel to the discharge lamp 4, 6 is a current detection resistor, and the resistor 6.
A series circuit consisting of a discharge lamp 4, an inductance 3, and a transistor 2 is connected in parallel to a DC power supply 1. 7 is a diode connected in antiparallel to the inductance 3 and the discharge lamp 4, 8 is a Zener diode, e is a resistor connected in parallel to the Zener diode 8, 1o is a transistor, 1
1 is a resistor, 12 is a resistor 13 connected in parallel to the discharge lamp 4
and 14, a discharge lamp voltage detection circuit which is a series circuit, 15 is a secondary winding with an inductance of 3, 16 is a diode, and 17
is a resistor, 18 is a resistor connected between the base and emitter of transistor 19, 2o is Zener diode 8, transistor 19.1o, diode 16, and resistor 6.9.1
This is a control circuit consisting of 1, 17, and 18.

This operation will be explained below. A current is supplied from the positive output terminal of the DC power supply 1 to the base of the transistor 2 via the resistors 9 and 11, and the transistor 2 is turned on. transistor 2
When turned on, current flows from the positive output terminal of the DC power supply 1 to the negative output terminal of the DC power supply 1 via the current detection resistor 6, the discharge lamp 4, the capacitor 5, the interface 3, and the emitter of the collector transistor 2 of the transistor 2. . This current is limited by the discharge lamp 4 and the inductance 3 and increases linearly. Therefore, the voltage across the resistor 6 also increases accordingly. Further, the voltage of the discharge lamp 4 is divided by a discharge lamp voltage detection circuit. On the other hand, the control circuit 20 continues to supply current to the base of the transistor 2 via the resistors 9 and 11. In addition, the resistor 9 is connected to the Zener diode 8.
The voltage at the dividing point of the resistor 9 connected to the emitter of the transistor 1o is also constant. Since the base of the transistor 1o is connected to the output of the discharge lamp voltage detection circuit, a constant voltage of a part of the resistor 9 and the discharge lamp voltage detection circuit 12 are connected between the base and emitter of the transistor 10.
The output voltage of and the voltage of resistor 6 are added. Therefore, resistance 6
When the voltage of the resistor 6 is small, the transistor 10 is off, and when the voltage applied between the base and emitter of the transistor 10, where the voltage of the resistor 6 is large, exceeds the voltage required to turn on the transistor 1o, the transistor 1o is turned on.

When transistor 1o is turned on, current flows from the collector of transistor 1o to the base of transistor 19. Therefore, transistor 19 short-circuits the base and emitter of transistor 2. Therefore, transistor 2
turns off, and the electromagnetic energy accumulated in the inductance 3 immediately before that causes a current to flow through the discharge lamp 4 via the diode 7. At this time, a constant voltage is generated in the secondary winding 15. diode 16 and resistor 17
A current is continued to be supplied to the base of the transistor 19 through the inductance 3 until the electromagnetic energy of the inductance 3 is exhausted, thereby keeping the transistor 2 off. When the base current no longer flows through transistor 19, transistor 19 is turned off and transistor 2 is turned on, returning to the original operation.

Problems to be Solved by the Invention In such conventional discharge lamp lighting devices or stabilized power supplies, in order to keep the discharge lamp voltage constant, a discharge lamp voltage detection circuit 12 is connected to the discharge lamp 4, and a Zener diode 8 is connected to the discharge lamp voltage detection circuit 12. A constant voltage power supply 21 consisting of a resistor 9 and a current detecting resistor 6 is provided.
The sum of the voltage and the output voltage of the discharge lamp voltage detection circuit 12 is kept constant. However, in this case, a constant voltage power supply 21 is required. in general,
The constant voltage power supply 21 is constructed using a Zener diode, but it is necessary to allow a relatively large current to flow through the Zener diode, and the output voltage of the DC power supply 1 is generally used as the power supply. Therefore, a large loss occurs in the constant voltage power supply 21, which reduces the efficiency of the discharge lamp lighting device, and also increases heat generation in the circuit, which makes it impossible to downsize the discharge lamp lighting device and reduces the reliability of the circuit. was there. Furthermore, in order to solve this problem, if a constant voltage is created using the voltage of the secondary winding 15 as a power source, the voltage becomes small and the configuration becomes complicated, such as by using an IC.

Means for Solving the Problems The present invention solves these conventional problems, and includes a power supply whose output voltage has a constant polarity, and a controlled semiconductor switch connected to one end of the output terminal of the power supply. and a series circuit of a load and an inductance connected between the other end of the output end of the power source and the other end of the controlled semiconductor switch, and connected in parallel to the series circuit and in the opposite direction to the power source. a power supply voltage detection circuit connected in parallel to the power supply to detect the output voltage of the power supply; and a power supply voltage detection circuit connected in parallel to the power supply to detect the output voltage of the power supply;
an inductance voltage detection circuit connected in parallel to the series circuit of the next winding or inductance and the controlled semiconductor switch to detect the voltage of the inductance; The control circuit includes a control circuit that receives an output voltage and an output voltage of the inductance voltage detection circuit, and controls the controlled semiconductor switch on and off according to the voltage difference therebetween.

The present invention uses the above-described configuration to detect the output voltage of the DC power supply and the voltage of the inductance, and control the load voltage by controlling the controlled semiconductor switch on and off in relation to the voltage difference between the two. Therefore, it is possible to eliminate the constant voltage power supply inside the circuit of the power supply device.

Embodiment FIG. 1 is a configuration diagram of a power supply device in an embodiment of the present invention. In Figure 1, 31 is an AC power supply 32° rectifier circuit 3
3. DC power supply consisting of smoothing capacitor 34, 35/'i
a discharge lamp which is a load connected to the positive terminal of the DC power supply 31;
36 is an inductance connected in series to the discharge lamp 36;
37 is a transistor which is a controlled semiconductor switch whose collector is connected to the other end of the inductance 36; 38 is a current detection resistor connected open between the emitter of the transistor and the negative terminal of the DC power supply 31; 39 is a transistor in parallel with the discharge lamp 35; 40 is a diode connected in anti-parallel to the discharge lamp 35 and inductance 36, 41 is 1 to the DC power supply 31! l: A power supply voltage detection circuit consisting of a series circuit of resistors 42 and 43 connected in parallel via a temporary detection resistor 38 and outputting the corresponding voltage; 44 is an inductance voltage detection circuit consisting of a series circuit of resistors 46 and 46. , 47 is an inductance 36 whose one end is connected to the negative terminal of the DC power supply 31.
The inductance voltage detection circuit 44 is connected in parallel to the secondary winding 47 and outputs a corresponding voltage.

48 is a transistor in which the output of the power supply voltage detection circuit 41 is connected to the base and the output of the inductance voltage detection circuit 44 is connected to the emitter; 49 is a transistor in which the collector of the transistor 48 is connected to the base and the emitter is connected to the secondary winding 47; , 5o and 61 are resistors connected in series between the collector of the transistor 49 and the negative terminal of the DC power supply 31, and 52 is a resistor whose base is connected between the resistors 60 and 51 and whose emitter is connected to the negative terminal of the DC power supply 31. 63, a resistor connected between the base of the transistor 37 and the secondary winding 47; 5411-1. A speed-up capacitor connected to the resistor 53, 55 is the base of the transistor 37.
A resistor connected between the emitters, 56 is a transistor 37
a starting resistor connected between the collector bases of 57
is a control circuit that controls on/off the transistor 37, which is composed of transistors 48, 49, 52, a capacitor 64, and a resistor 38, 50, 51, 53, 55, 56.

The operation of the embodiment shown in FIG. 1 will be explained below.

The voltage of the AC power supply 32 is rectified by the rectifier circuit 33, and the pulsating voltage that is the output thereof is smoothed by the smoothing capacitor 34, and becomes the output of the DC power supply 31. This output voltage v, n
When the transistor 37 is turned on via the resistor 56, current flows from the DC power supply 31 to the capacitor 39 and the discharge lamp 35 via the inductance 36, the transistor 37, and the resistor 38. This current has an inductance of 3
6 and the discharge lamp 36 and increases linearly.

Therefore, a constant voltage is generated in the secondary winding 47 of the inductance 36, and this voltage supplies the base current of the transistor 37 through the resistor 63 to maintain the transistor 37 in an on state. The current flowing through the inductance 36 increases and the voltage across the current detection resistor 38 increases. At this time,
The voltage between the base B and emitter E of the transistor 48 BE48 is the voltage of the resistor 43 which is the output of the power supply voltage detection circuit 41, the voltage of the resistor 4e which is the output of the inductance voltage detection circuit 44, and the current detection resistor 38. , and the transistor 48 is initially off. Here, when the BE voltage vBE4B of the transistor 48 reaches a predetermined value, a stain current flows through the power supply voltage detection circuit 41 to the base of the transistor 48, and the transistor 48 is turned on. When the transistor 48 is turned on, the transistor 49 is also turned on, and current flows from the secondary winding 47 through the emitter and collector of the transistor 49 to the resistors 6o and 51.

At the same time, current flows to the base of transistor 620, turning on transistor 52 as well. Therefore, transistor 37
The collector-emitter of the transistor 37 is short-circuited, and the transistor 37 is turned off. When the transistor 37 is turned off, the electromagnetic energy stored in the inductance 36 immediately before this is supplied to the discharge lamp 35 via the diode 4o during the off period of the transistor 37. At this time, the secondary winding 47
A negative voltage is generated, and the transistor 37 is kept off via the control circuit 57. When the energy in the inductance 36 is exhausted, the base current flows to the transistor 37 via the resistor 66 again, and the transistor 3
7 turns on and repeats the first operation.

In the above operation, when the transistor 37 is last in the on state, that is, when the transistor 48 is turned on, the base voltage vB48 of the transistor 48 is: ■B48:■1nxR43/(R43+R42)+R3
Emitter voltage of 8x Cp transistor 48 E48 is vE48=vL2×R4e/ (R46+R45)
The voltage vL2 of the secondary winding 47 is: *L2""L1/"=(vin-vAa)/". However, n is the inductance 36 and its secondary winding 4
7, vLl is the voltage of the inductance 36,
■Yu. is the voltage of the discharge lamp 36, and Cp is the current detection resistor 3
This is the peak value of the current flowing through 8.

Here, the base-emitter voltage vBE48 when the transistor 48 is turned on is as follows: BE48 = "R48-■
E48, which is constant depending on the device. From the above equation, the voltage vIV,a of the discharge lamp 35 is as follows. From the formula for v1a above, the resistance is 38, 42°43.
By adjusting 45.46 and turns ratio n, vi
nl! :The relationship between vfia and ICp can be set arbitrarily. Also, discharge lamp electrician, =I. p/2, and
The discharge lamp power Wfta is WEa=Vmm x Imm. Therefore, by adjusting the resistance and the turns ratio, vtn, VB, , Im, and Wla can be set arbitrarily. In this case, if the term related to vin is set to zero, ■h is determined by Icp, and “4
2 a is determined by ■mu. In other words, it is.

Also, its differential coefficient dWmu/dVyu is. The above dWAa/dV, a is the discharge lamp voltage vfta
If set to zero when is rated, vfia
This value is negative if vm is large, and positive if vm is small. In general, discharge lamps have positive static characteristics,
Increasing IAa (ie, p) increases Wm, which in turn increases vEa. This is particularly noticeable when the discharge lamp is of the saturated vapor pressure type. Therefore, if h is larger than the rated value, the power supplied to the lamp will be small.
The opposite is true if Aa is smaller than the rating. the result,
■The system stabilizes at the rated setting value. Furthermore, since the term related to vinK is set to zero, there is no variation in vRa due to variation in viU.

As described above, in this embodiment, when the transistor 37 is turned on, the voltage of the inductance 36 is transformed by the secondary winding 47, and the difference between the resulting voltage and the output voltage of the DC power supply 31 is used. By controlling the transistor 37 on and off, the voltage vRa of the discharge lamp 35 can be controlled to be constant with a simple configuration without providing a constant voltage power supply section in the control circuit 57. Therefore, the control circuit 57 can have low power consumption,
The loss of the entire discharge lamp lighting device can also be reduced. In addition, by adjusting other terms related to V, the load can be controlled to have arbitrary characteristics n. In addition, in this embodiment, since the voltage of the inductance 36 is transformed by the secondary winding a47,
The loss in the inductance voltage detection circuit 44 can also be reduced. Furthermore, the influence of ■iyu can be eliminated with a simple configuration. As described above, according to this embodiment, the discharge lamp lighting device can be made more efficient, simple, compact, lightweight, and inexpensive.

In addition, it is highly reliable and can be used safely.

In the above embodiment, the inductance voltage was detected from the secondary winding 47, but the inductance voltage detection circuit 4
4 is connected to the negative terminal of the DC power supply 31 and the inductance 3
The inductance voltage may be directly detected via the transistor CE and the discharge lamp 35 by connecting it between the transistor CE and the discharge lamp 35.

In this case, the output voltage of the detection circuit can be increased and control becomes easier. Further, in this embodiment, the order of the discharge lamp 36 and the inductance 36 may be reversed.

In addition, although the DC power supply 31 used was a rectified AC power source,
A DC power source such as a battery may be used. Further, although an npn transistor is used as the controlled semiconductor switch, other types may be used. In addition, the control circuit 67 uses the secondary winding 47 as a power source, detects the instantaneous current with a current detection resistor 38, and detects the instantaneous current with the transistor 3.
7 is controlled on and off, however, it is also possible to use one that detects the average current, one that uses another oscillation method, or one that uses an IC. Alternatively, the transistor 48 may be of any other type as long as it functions as a comparator. Moreover, the same effect can be obtained even if the power supply voltage detection circuit 41 and the inductance voltage detection circuit 44 are provided with a bias voltage source using the pace-emitter voltage of the transistor 37 internally due to the relationship with the control circuit 67. . Further, in this embodiment, the terminal connecting the secondary winding 47 to the negative terminal of the DC power supply 31 may be connected to the emitter of the transistor 37. Further, although a self-excited step-down chipper system using a secondary winding of the inductance 36 is used as the power supply device, other self-excited or separately excited step-down chopper systems may be used. Further, in this embodiment, the load is a discharge lamp, but other impedance loads or electronic devices may be used.

Effects of the Invention As described above, the power supply device of the present invention has a simple configuration with little loss, can arbitrarily control the load, and can be made highly efficient, compact, and lightweight.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing the configuration of an embodiment of the present invention, and FIG. 2 is a circuit diagram of a conventional power supply device. 31...DC power supply, 35...Discharge lamp, 36
...Inductance, 37...Transistor, 40...Diode, 41...Power supply voltage detection circuit, 44...Inductance voltage detection circuit, 57...・−・Control circuit.

Claims (1)

[Claims] A power supply whose output voltage has a constant polarity, a controlled semiconductor switch connected to one end of the output terminal of the power supply, and a connection between the other output terminal of the power supply and the other end of the controlled semiconductor switch. A series circuit with a load and an inductance,
a diode connected in parallel to the series circuit and in a reverse direction to the power supply; a power supply voltage detection circuit connected in parallel to the power supply to detect the output voltage of the power supply; and a power supply voltage detection circuit connected in parallel to the power supply to detect the output voltage of the power supply; or an inductance voltage detection circuit connected in parallel to a series circuit of the secondary winding or inductance and the controlled semiconductor switch to detect the voltage of the inductance; and an inductance voltage detection circuit connected to the control terminal of the controlled semiconductor switch and connected to the power supply voltage. A power supply device comprising a control circuit that receives an output voltage of a detection circuit and an output voltage of the inductance voltage detection circuit, and controls the controlled semiconductor switch on and off according to the voltage difference between the two.