JPH0572191B2 - - Google Patents
Info
- Publication number
- JPH0572191B2 JPH0572191B2 JP57062249A JP6224982A JPH0572191B2 JP H0572191 B2 JPH0572191 B2 JP H0572191B2 JP 57062249 A JP57062249 A JP 57062249A JP 6224982 A JP6224982 A JP 6224982A JP H0572191 B2 JPH0572191 B2 JP H0572191B2
- Authority
- JP
- Japan
- Prior art keywords
- voltage
- oscillation
- resistor
- circuit
- output
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 230000010355 oscillation Effects 0.000 claims description 76
- 239000003990 capacitor Substances 0.000 claims description 22
- 238000004804 winding Methods 0.000 claims description 21
- 230000008929 regeneration Effects 0.000 claims description 19
- 238000011069 regeneration method Methods 0.000 claims description 19
- 230000000087 stabilizing effect Effects 0.000 claims description 6
- 238000010586 diagram Methods 0.000 description 8
- 230000002159 abnormal effect Effects 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 230000000630 rising effect Effects 0.000 description 2
- 230000003321 amplification Effects 0.000 description 1
- 230000002238 attenuated effect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000020169 heat generation Effects 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
- 238000005192 partition Methods 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
- 230000002459 sustained effect Effects 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of DC power input into DC power output
- H02M3/22—Conversion of DC power input into DC power output with intermediate conversion into AC
- H02M3/24—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters
- H02M3/28—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC
- H02M3/325—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC using devices of a triode or a transistor type requiring continuous application of a control signal
- H02M3/335—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Inverter Devices (AREA)
Description
【発明の詳細な説明】
本発明は、自励発振型の高圧電源に係り、自動
復帰型保護回路を備えた高圧電源に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a self-oscillation type high-voltage power supply, and more particularly, to a high-voltage power supply equipped with an automatic reset type protection circuit.
従来のこの種の高圧電源は、第１図のブロツク
回路図に示すようにシユミツト回路を用いて保護
回路が構成されている。この第１図の高圧電源は
次のように作動する。つまり、高圧出力Voutが
短絡すると、フイードバツク電圧Vfが零となる
ためその信号が比較増幅回路で増幅されて制御回
路の出力電圧VBを上昇させる。制御回路の出力
電圧VBが上昇すると、この電圧をシユミツト回
路が検知し、発振トランジスタのベース回路のベ
ース電流を遮断して発振を停止させる。それと同
時に、このシユミツト回路によつて比較増幅回路
の制御回路への供給電圧を遮断してその出力電圧
VBを低下させ、それによりシユミツト回路を
OFFとし、自動復帰動作をする。これにより発
振トランジスタのベース電流が流れ始めて発振を
開始しようとするが、いまだ高圧出力Voutが短
絡していると、上述動作の繰り返しによつて制御
回路の出力電圧VBが再び上昇してシユミツト回
路をONとするため発振できないことになる。第
２図は、この制御回路の出力電圧VBが変化する
状態を示しており、高圧出力Voutが短絡してい
る限り、出力電圧VBはシユミツト回路のOFFレ
ベルとONレベルの間において上昇、下降を繰り
返すことになるのである。従来の保護回路を備え
た高圧電源はこのような動作をするものであり、
シユミツト回路のOFFレベルからONレベルまで
の出力電圧VBの立上り期間αは保護回路の非動
作領域となるため、この期間で発振トランジスタ
のベースには最大値の電流が流れることになる。
そのため、発振回路が異常発振を起こして出力回
路に流れる短絡電流が大きくなり安全上の問題が
生じる虞れがある。また、上記従来のものは、シ
ユミツト回路の作動レベルを設定しなければなら
ないものであるため、正常時の制御回路の出力電
圧は、シユミツト回路のONレベル以下に設定し
なければならず、そのため、制御回路での電圧降
下が大きくなつて効率が悪くなり、大きな発熱が
生じるという問題がある。また、シユミツト回路
およびこれに付随する自動復帰回路を構成しなけ
ればならないことから回路構成が煩雑となり、さ
らには上述のように大きな発熱が生じることから
放熱器を大型化しなければならない等の理由によ
りコスト的に不利になるとともに、装置が大型化
する等の問題がある。 In a conventional high voltage power supply of this type, a protection circuit is constructed using a Schmitt circuit as shown in the block circuit diagram of FIG. The high voltage power supply of FIG. 1 operates as follows. That is, when the high voltage output Vout is short-circuited, the feedback voltage V f becomes zero, so the signal is amplified by the comparison amplifier circuit and increases the output voltage V B of the control circuit. When the output voltage V B of the control circuit rises, the Schmitt circuit detects this voltage and cuts off the base current of the base circuit of the oscillation transistor to stop oscillation. At the same time, this Schmitt circuit cuts off the supply voltage to the control circuit of the comparison amplifier circuit and reduces its output voltage.
V B , thereby reducing the Schmitt circuit.
Turn it OFF and perform automatic recovery operation. As a result, the base current of the oscillation transistor begins to flow and it attempts to start oscillation, but if the high voltage output Vout is still short-circuited, the output voltage V B of the control circuit rises again due to the repetition of the above operation, and the Schmitt circuit Since it is turned on, oscillation cannot occur. Figure 2 shows the state in which the output voltage V B of this control circuit changes. As long as the high voltage output Vout is short-circuited, the output voltage V B increases between the OFF level and the ON level of the Schmitt circuit. It will continue to decline. A high-voltage power supply with a conventional protection circuit operates like this.
Since the rising period α of the output voltage V B from the OFF level to the ON level of the Schmitt circuit is the non-operating region of the protection circuit, the maximum current flows through the base of the oscillation transistor during this period.
Therefore, there is a risk that the oscillation circuit will cause abnormal oscillation and the short-circuit current flowing through the output circuit will increase, causing a safety problem. In addition, in the above conventional system, the operating level of the Schmitt circuit must be set, so the output voltage of the control circuit during normal operation must be set below the ON level of the Schmitt circuit. There is a problem in that the voltage drop in the control circuit becomes large, the efficiency deteriorates, and a large amount of heat is generated. In addition, the circuit configuration becomes complicated because a Schmitt circuit and an associated automatic reset circuit must be configured, and furthermore, as mentioned above, large heat is generated, so the heat sink must be made larger. There are problems such as being disadvantageous in terms of cost and increasing the size of the device.
本発明は、このような点に鑑みてなされたもの
で、保護回路の動作特性を向上させるとともに、
保護回路の構成を簡素化せしめて発熱の低減およ
び装置の小型化を図り、コスト的にも有利な高圧
電源を提供することを目的とする。このため、本
発明は、高圧トランスの入力巻線の一端を発振ト
ランジスタのコレクタに接続し、他端を制御入力
端に加わる信号により制御される直流電圧を出力
する制御回路の一方の出力端に接続し、発振トラ
ンジスタのエミツタを制御回路の他方の出力端に
接続し、発振トランジスタのベース・エミツタ間
に正帰還巻線、発振安定化抵抗、再生用コンデン
サを直列に接続し、発振安定化抵抗と再生用コン
デンサの接続点と入力巻線の他端と制御回路の出
力端の接続点間に複数個のベース抵抗からなる第
１抵抗回路部を接続し、第１抵抗回路部に並列
に、発振トランジスタのベース電流の絞り込みを
行なうツエナーダイオードと抵抗体が直列接続さ
れてなる第２抵抗回路部を接続し、第２抵抗回路
部に並列に、起動時にベース電流を流し込むため
の抵抗体からなる第３抵抗回路部を接続し、制御
回路の制御入力端と発振トランジスタのエミツタ
間に接続された保護用トランジスタのベースに第
１抵抗回路部の抵抗体の分圧出力を接続し、制御
回路の制御入力端に高圧トランスの出力巻線から
帰還される出力の一部と基準電圧を比較して制御
回路を制御する比較増幅器の出力を接続し、第１
抵抗回路部の各抵抗値は発振トランジスタの発振
の減衰に伴い再生用コンデンサの電圧が上昇した
場合に、分圧出力が保護用トランジスタのオン電
圧を超えるように設定され、ツエナーダイオード
のツエナー電圧は、正常発振時の制御回路の出力
電圧よりも低く設定されていることを特徴とする
ものである。つまり、第３図に示すものは従来の
自励発振型高圧電源のコレクタ同調発振回路部分
であり、１は入力端子、２は同調コンデンサ、３
は発振トランジスタ、４はベース抵抗、５は再生
用コンデンサ、６は正帰還巻線、７は発振安定化
抵抗であつて、このような発振回路においては、
発振トランジスタ３のON期間には、正帰還巻線
６により発振が持続されて再生用コンデンサ５に
充電電圧Ib1が流れ、この再生用コンデンサ５の
電圧Vbは負の値となる。そして、発振トランジ
スタ３がOFFになつたときには、再生用コンデ
ンサ５で充電された電荷が放電電流Ib2によつて
ベース抵抗４を介して放電する。発振回路が発振
状態にあるときには、再生用コンデンサ５は上記
のような充放電を繰り返し、その電圧Vbは、第
４図に示すような三角波形となり、常に負の値と
なる。そして、高圧出力が短絡したとき、自励発
振回路の有する垂下特性で発振が停止し、正帰還
巻線６の誘起電圧は消滅する。このとき、発振ト
ランジスタ３にはベース抵抗４を介してベース電
流が流れ、このトランジスタの電流増幅率倍の異
常電流が流れる。そして、高圧出力が零であるた
め、制御系が動作して制御回路の出力電圧VBは
最大値にまで上昇し、電力損失が増大して、発振
トランジスタ３は熱破壊にいたる。このような熱
破壊に至るまでの状態を発振トランジスタ３の直
流動作と呼ぶ。 The present invention has been made in view of these points, and improves the operating characteristics of a protection circuit, and
It is an object of the present invention to provide a high-voltage power supply that is advantageous in terms of cost by simplifying the configuration of a protection circuit to reduce heat generation and downsize the device. Therefore, the present invention connects one end of the input winding of the high-voltage transformer to the collector of the oscillation transistor, and connects the other end to one output end of a control circuit that outputs a DC voltage controlled by a signal applied to the control input end. Connect the emitter of the oscillation transistor to the other output terminal of the control circuit, and connect a positive feedback winding, an oscillation stabilizing resistor, and a regeneration capacitor in series between the base and emitter of the oscillating transistor. A first resistor circuit section consisting of a plurality of base resistors is connected between the connection point of the regeneration capacitor, the other end of the input winding, and the output end of the control circuit, and is connected in parallel to the first resistance circuit section. A second resistor circuit section is connected in which a Zener diode and a resistor are connected in series to narrow down the base current of the oscillation transistor, and a resistor is connected in parallel to the second resistor circuit section to flow the base current at startup. The third resistor circuit section is connected, and the divided voltage output of the resistor of the first resistor circuit section is connected to the base of the protection transistor connected between the control input terminal of the control circuit and the emitter of the oscillation transistor. The output of a comparator amplifier that controls the control circuit by comparing a part of the output fed back from the output winding of the high-voltage transformer with a reference voltage is connected to the control input terminal.
The resistance values of the resistor circuit are set so that when the voltage of the regeneration capacitor increases as the oscillation of the oscillation transistor attenuates, the divided voltage output exceeds the on-voltage of the protection transistor, and the Zener voltage of the Zener diode increases. , the output voltage of the control circuit is set lower than the output voltage of the control circuit during normal oscillation. In other words, what is shown in Fig. 3 is the collector-tuned oscillation circuit part of a conventional self-oscillation type high-voltage power supply, where 1 is an input terminal, 2 is a tuning capacitor, and 3
is an oscillation transistor, 4 is a base resistor, 5 is a regeneration capacitor, 6 is a positive feedback winding, and 7 is an oscillation stabilizing resistor. In such an oscillation circuit,
During the ON period of the oscillation transistor 3, oscillation is sustained by the positive feedback winding 6, and the charging voltage I b1 flows to the regeneration capacitor 5, and the voltage Vb of the regeneration capacitor 5 takes a negative value. Then, when the oscillation transistor 3 is turned off, the charge charged in the regeneration capacitor 5 is discharged via the base resistor 4 by the discharge current I b2 . When the oscillation circuit is in an oscillation state, the regeneration capacitor 5 repeats charging and discharging as described above, and the voltage V b has a triangular waveform as shown in FIG. 4 and always takes a negative value. When the high-voltage output is short-circuited, oscillation is stopped due to the drooping characteristic of the self-excited oscillation circuit, and the induced voltage in the positive feedback winding 6 disappears. At this time, a base current flows through the oscillation transistor 3 via the base resistor 4, and an abnormal current that is twice the current amplification factor of this transistor flows. Since the high voltage output is zero, the control system operates and the output voltage V B of the control circuit increases to its maximum value, increasing power loss and causing thermal breakdown of the oscillation transistor 3. The state leading up to such thermal breakdown is called DC operation of the oscillation transistor 3.
本発明は、上記のように発振回路の発振時には
再生用コンデンサ５の電圧Vbが負電位領域に存
在し、高圧出力の短絡時の発振停止による発振ト
ランジスタ３の直流動作で（この時、再生用コン
デンサ５は正帰還巻線が発振停止により交流動作
をしなくなる為、動作しない）Vb＝VBE＋Ib・Rb
（ここでVBEは発振トランジスタ３のベース・エ
ミツタ間電圧値、Rbは発振安定化抵抗７の抵抗
値、Ibはそこを流れる電流値を表わす）の電位と
なることを利用して保護回路を構成したものであ
る。 As mentioned above, when the oscillation circuit oscillates, the voltage V b of the regeneration capacitor 5 exists in the negative potential region, and the DC operation of the oscillation transistor 3 due to the oscillation stop when the high voltage output is short-circuited (at this time, the regeneration Capacitor 5 does not operate because the positive feedback winding stops oscillating and does not perform AC operation) V b = V BE +I b・R b
(Here, V BE is the voltage value between the base and emitter of the oscillation transistor 3, R b is the resistance value of the oscillation stabilizing resistor 7, and I b is the current value flowing through it.) It consists of a circuit.
以下に本発明の一実施例を図面を参照して詳細
に説明する。 An embodiment of the present invention will be described in detail below with reference to the drawings.
第５図において、１は高圧トランスＴの入力巻
線、２は同調コンデンサ、３は発振トランジス
タ、５は再生用コンデンサ、６は正帰還巻線、７
は発振安定化抵抗で、これらの構成は上記従来の
ものと同様である。８，９は互いに直列接続して
なる発振トランジスタ３のベース抵抗の一部を構
成する抵抗体で、第１抵抗回路部を構成するもの
である。この第１抵抗回路部は、発振トランジス
タ３のベース電流を流すことが主目的ではなく、
高圧出力の短絡の有無を検出するための短絡検出
回路を構成するものであるため、特に抵抗体８が
高抵抗値に設定されて高抵抗回路を構成してい
る。１０は電圧安定化のための制御回路、１１は
この制御回路１０に接続された保護用トランジス
タで、第１抵抗回路部を形成している抵抗体８，
９の接続点の電圧Vcによつて動作し、制御回路
１０を制御するものである。１２はカソードが制
御回路１０の出力側に接続されたツエナーダイオ
ード、１３は発振トランジスタ３のベース抵抗の
一部を構成する抵抗体で、ツエナーダイオード１
２に直列接続されてツエナーダイオード１２とと
もに第２抵抗回路部を形成し、第１抵抗回路部に
並列接続されたものである。この第２抵抗回路部
は、発振トランジスタ３のベース電流を主に流す
主ベース電流回路を構成するものであるため、抵
抗体１３は低い値に設定されている。１４は発振
トランジスタ３のベース抵抗の一部を構成する抵
抗体で、第３抵抗回路部を形成し、第１、第２抵
抗回路部に並列接続されたものである。この第３
抵抗回路部は、高圧出力が短絡状態から解除され
たときに発振回路の発振を正常状態に復帰させる
ための発振起動用と、正常動作状態の起動時にお
ける制御回路１０の出力電圧がツエナーダイオー
ド１２のツエナー電圧値以上に上昇するまでの立
上がり期間に、発振トランジスタ３のベース電流
を流す発振起動用のものであるため、抵抗体１４
は比較的高抵抗値に設定されている。上記の説明
から明らかなように、第１、第２および第３抵抗
回路部はそれぞれ異なつた目的を有しているが、
それらは互いに並列接続されて発振トランジスタ
３のベース抵抗を構成している。１５は高圧トラ
ンスＴの出力側巻線、１６はこの巻線に接続され
た整流回路、１７はこの整流回路１６の出力の一
部と基準電圧とを比較増幅して前記制御回路を制
御する比較増幅器である。なお、高圧出力が交流
を必要とする場合には、整流回路１６は不要であ
る。 In Fig. 5, 1 is the input winding of the high voltage transformer T, 2 is the tuning capacitor, 3 is the oscillation transistor, 5 is the regeneration capacitor, 6 is the positive feedback winding, and 7 is the input winding of the high voltage transformer T.
is an oscillation stabilizing resistor, and the configuration thereof is the same as that of the above-mentioned conventional one. Reference numerals 8 and 9 denote resistors that constitute a part of the base resistance of the oscillation transistor 3, which are connected in series with each other, and constitute a first resistor circuit section. The main purpose of this first resistance circuit section is not to flow the base current of the oscillation transistor 3;
Since it constitutes a short circuit detection circuit for detecting the presence or absence of a short circuit in the high voltage output, the resistor 8 in particular is set to a high resistance value to constitute a high resistance circuit. 10 is a control circuit for voltage stabilization, 11 is a protection transistor connected to this control circuit 10, and a resistor 8 forming a first resistance circuit section.
The control circuit 10 is operated by the voltage V c at the connection point 9 and controls the control circuit 10 . 12 is a Zener diode whose cathode is connected to the output side of the control circuit 10; 13 is a resistor forming part of the base resistance of the oscillation transistor 3;
2 to form a second resistance circuit section together with the Zener diode 12, and connected in parallel to the first resistance circuit section. Since this second resistance circuit section constitutes a main base current circuit through which the base current of the oscillation transistor 3 mainly flows, the resistor 13 is set to a low value. A resistor 14 constitutes a part of the base resistance of the oscillation transistor 3, forms a third resistor circuit section, and is connected in parallel to the first and second resistor circuit sections. This third
The resistor circuit section is used for starting oscillation to return the oscillation of the oscillation circuit to the normal state when the high voltage output is released from the short-circuit state, and the output voltage of the control circuit 10 at the time of starting the normal operating state is connected to the Zener diode 12. The resistor 14 is used to start the oscillation, which causes the base current of the oscillation transistor 3 to flow during the rising period until the Zener voltage rises above the Zener voltage value.
is set to a relatively high resistance value. As is clear from the above description, the first, second and third resistor circuit sections each have different purposes;
They are connected in parallel to each other and constitute the base resistance of the oscillation transistor 3. 15 is an output winding of the high-voltage transformer T, 16 is a rectifier circuit connected to this winding, and 17 is a comparator that compares and amplifies a part of the output of the rectifier circuit 16 with a reference voltage to control the control circuit. It's an amplifier. Note that if the high voltage output requires alternating current, the rectifier circuit 16 is not necessary.
このような回路構成において、発振回路が正常
な発振状態にあるときには、ツエナーダイオード
１２のツエナー電圧は、制御回路１０の出力電圧
VBよりも低くなるように設定されており、その
ため、第１、第２および第３抵抗回路部にそれぞ
れ発振トランジスタ３のベース電流が流れてい
る。ただし、ベース電流の分割割合は、抵抗値の
低い第２抵抗回路部が最も大きいことはいうまで
もない。第１抵抗回路部を形成している抵抗体
８，９の接続点の電圧Vcは、第６図に示すよう
に、再生用コンデンサ５の電圧Vbに抵抗体９の
値により決まる直流バイアスをかけた状態で推移
する。いま、発振回路が正常な発振状態にあると
きには、この電圧Vcは保護用トランジスタ１１
のON電圧よりも低い値になるように設定されて
いるため、保護用トランジスタ１１はOFF状態
に維持されている。ところが、高圧出力が短絡す
ると（短絡時になると）、発振が減衰することに
よつて再生用コンデンサ５の電圧Vbが上昇（交
流動作から直流動作への移行）し、これによつて
抵抗体８，９の接続点の電圧Vcも上昇して、つ
いには保護用トランジスタ１１のONレベルの電
位に達し、その結果、保護用トランジスタ１１が
ON状態となつて制御回路１０の出力電圧VBを減
少させる。このときの、制御回路１０の出力電圧
VBは、VB＝VBE1＋R1（VBE1−VBE2）／R2（ここ
で、VBE1は保護用トランジスタ１１のベース・エ
ミツタ間電圧値、VBE2は発振トランジスタ３のベ
ース・エミツタ間電圧値、R1は抵抗体８の抵抗
値、R2は抵抗体９の抵抗値をそれぞれ表す。）で
示されるもので、ツエナーダイオード１２のツエ
ナー電圧は制御回路１０の出力電圧VBよりも高
く設定されている。そのため、ツエナーダイオー
ド１２と抵抗体１３とで形成されている発振トラ
ンジスタ３の主ベース電流回路である第２抵抗回
路は遮断されてしまい、ベース電流は高抵抗回路
である第１および第３抵抗回路部にしか流れない
ことになつて発振トランジスタ３の発振はきわめ
て微弱な状態となり、高圧出力の短絡から電源を
保護する。 In such a circuit configuration, when the oscillation circuit is in a normal oscillation state, the Zener voltage of the Zener diode 12 is equal to the output voltage of the control circuit 10.
It is set to be lower than VB , so that the base current of the oscillation transistor 3 flows through the first, second, and third resistance circuit sections, respectively. However, it goes without saying that the base current division ratio is greatest in the second resistor circuit section having a lower resistance value. As shown in FIG. 6, the voltage V c at the connection point of the resistors 8 and 9 forming the first resistor circuit section is the DC bias determined by the voltage V b of the regeneration capacitor 5 and the value of the resistor 9. It remains in a state where it is multiplied by . Now, when the oscillation circuit is in a normal oscillation state, this voltage V c is applied to the protection transistor 11.
Since the protection transistor 11 is set to a value lower than the ON voltage of , the protection transistor 11 is maintained in an OFF state. However, when the high-voltage output is short-circuited (in the event of a short-circuit), the oscillation is attenuated and the voltage V b of the regeneration capacitor 5 increases (transition from AC operation to DC operation), which causes the resistor 8 , 9 also rises, and finally reaches the ON level potential of the protection transistor 11, and as a result, the protection transistor 11 turns on.
It becomes ON state and reduces the output voltage V B of the control circuit 10. At this time, the output voltage of the control circuit 10
V B is V B = V BE1 + R 1 (V BE1 − V BE2 )/R 2 (where, V BE1 is the base-emitter voltage value of the protection transistor 11, and V BE2 is the base-emitter voltage value of the oscillation transistor 3. The Zener voltage of the Zener diode 12 is determined by the output voltage V B of the control circuit 10. It is also set high. Therefore, the second resistance circuit, which is the main base current circuit of the oscillation transistor 3 formed by the Zener diode 12 and the resistor 13, is cut off, and the base current is passed through the first and third resistance circuits, which are high resistance circuits. As a result, the oscillation of the oscillation transistor 3 becomes extremely weak, and the power supply is protected from a short circuit of the high voltage output.
そして、高圧出力の短絡が解除されたときに
は、発振トランジスタ３は小さなベース電流で発
振するため、短絡時には微弱な発振状態にあつた
ものが、主に第３の抵抗回路に流れるベース電流
によつて発振が成長し始め、その結果、再生用コ
ンデンサ５が急速に負に充電されてVbの値が急
速に負電位になる。すると、第１抵抗回路部の抵
抗体８，９の接続点の電圧Vcが急速に小さくな
つて、保護用トランジスタ１１のOFFレベルの
電位となり、制御回路１０の出力電圧VBは正常
値に戻ることになる。これにより、ツエナーダイ
オード１２が導通状態となつて主ベース電流回路
である第２抵抗回路部に所要のベース電流が流れ
るようになり、発振トランジスタ３の発振が急激
に正常状態に復帰することになる。このようなツ
エナーダイオード１２は、保護用トランジスタ１
１がONして出力電圧VBを減少させたときのしぼ
り込みによる主ベース電流を防止するための電圧
の仕切値を決定している。 When the short circuit of the high voltage output is released, the oscillation transistor 3 oscillates with a small base current, so that the weak oscillation state at the time of the short circuit is caused mainly by the base current flowing through the third resistor circuit. The oscillation begins to grow, and as a result, the regeneration capacitor 5 is rapidly charged negatively and the value of V b quickly becomes a negative potential. Then, the voltage V c at the connection point between the resistors 8 and 9 of the first resistor circuit section rapidly decreases to the OFF level potential of the protection transistor 11, and the output voltage V B of the control circuit 10 returns to a normal value. I will be going back. As a result, the Zener diode 12 becomes conductive, allowing the required base current to flow through the second resistor circuit, which is the main base current circuit, and the oscillation of the oscillation transistor 3 rapidly returns to its normal state. . Such a Zener diode 12 is connected to a protection transistor 1.
The voltage partition value is determined to prevent the main base current from being squeezed when the output voltage VB is reduced by turning on the voltage VB.
本発明の高圧電源は以上説明したように構成さ
れているので、保護動作および復帰特性に極めて
優れたものとなり、保護回路の構成が簡素化され
て小型化が促進され、コスト的にも極めて有利に
なる等の種々の優れた効果を奏する。 Since the high-voltage power supply of the present invention is configured as described above, it has extremely excellent protection operation and recovery characteristics, simplifies the configuration of the protection circuit, promotes miniaturization, and is extremely advantageous in terms of cost. It has various excellent effects such as:
第１図は従来の保護回路を備えた高圧電源のブ
ロツク回路図、第２図はその制御回路の高圧出力
短絡時の出力電圧波形図、第３図は従来の自励発
振回路図、第４図はその発振トランジスタの電圧
波形図および再生用コンデンサの電圧波形図、第
５図は本発明の一実施例の高圧電源の回路構成
図、第６図はその第１抵抗回路部および再生用コ
ンデンサの電圧波形図である。
１……高圧トランスの入力巻線、３……発振ト
ランジスタ、５……再生用コンデンサ、６……正
帰還巻線、７……発振安定化抵抗、８，９，１
３，１４……抵抗体、１０……制御回路、１１…
…保護用トランジスタ、１２……ツエナーダイオ
ード、１５……高圧トランスの出力巻線、１６…
…整流回路、１７……比較増幅器。
Figure 1 is a block circuit diagram of a high voltage power supply equipped with a conventional protection circuit, Figure 2 is an output voltage waveform diagram of the control circuit when the high voltage output is short-circuited, Figure 3 is a diagram of a conventional self-oscillation circuit, and Figure 4 is a diagram of a conventional self-oscillation circuit. The figure shows a voltage waveform diagram of the oscillation transistor and a voltage waveform diagram of the regeneration capacitor, Fig. 5 is a circuit configuration diagram of a high-voltage power supply according to an embodiment of the present invention, and Fig. 6 shows the first resistor circuit and the regeneration capacitor. FIG. 1... Input winding of high voltage transformer, 3... Oscillation transistor, 5... Regeneration capacitor, 6... Positive feedback winding, 7... Oscillation stabilizing resistor, 8, 9, 1
3, 14...Resistor, 10...Control circuit, 11...
...Protection transistor, 12... Zener diode, 15... Output winding of high voltage transformer, 16...
... Rectifier circuit, 17... Comparison amplifier.
Claims (1)
ジスタのコレクタに接続し、他端を制御入力端に
加わる信号により制御される直流電圧を出力する
制御回路の一方の出力端に接続し、前記発振トラ
ンジスタのエミツタを前記制御回路の他方の出力
端に接続し、前記発振トランジスタのベース・エ
ミツタ間に正帰還巻線、発振安定化抵抗、再生用
コンデンサを直列に接続し、該発振安定化抵抗と
再生用コンデンサの接続点と前記入力巻線の他端
と前記制御回路の出力端の接続点間に、複数個の
ベース抵抗からなる第１抵抗回路部を接続し、該
第１抵抗回路部に並列に、前記発振トランジスタ
のベース電流の絞り込みを行うツエナーダイオー
ドと抵抗体が直列接続されてなる第２抵抗回路部
を接続し、該第２抵抗回路部に並列に、起動時に
ベース電流を流し込むための抵抗体からなる第３
抵抗回路部を接続し、前記制御回路の制御入力端
と前記発振トランジスタのエミツタ間に接続され
た保護用トランジスタのベースに前記第１抵抗回
路部の抵抗体の分圧出力を接続し、前記制御回路
の制御入力端に前記高圧トランスの出力巻線から
帰還される出力の一部と基準電圧を比較して前記
制御回路を制御する比較増幅器の出力を接続し、
前記第１抵抗回路部の各抵抗値は前記発振トラン
ジスタの発振の減衰に伴い前記再生用コンデンサ
の電圧が上昇した場合に、分圧出力が前記保護用
トランジスタのオン電圧を超えるように設定さ
れ、前記ツエナーダイオードのツエナー電圧は、
正常発振時の制御回路の出力電圧よりも低く設定
されていることを特徴とする自励発振型高圧電
源。1. One end of the input winding of the high voltage transformer is connected to the collector of the oscillation transistor, the other end is connected to one output end of a control circuit that outputs a DC voltage controlled by a signal applied to the control input terminal, and the input winding of the high voltage transformer is connected to the collector of the oscillation transistor. The emitter of the oscillation transistor is connected to the other output terminal of the control circuit, and a positive feedback winding, an oscillation stabilizing resistor, and a regeneration capacitor are connected in series between the base and emitter of the oscillation transistor. A first resistor circuit section consisting of a plurality of base resistors is connected between the connection point of the capacitor and the connection point of the other end of the input winding and the output end of the control circuit. A second resistor circuit section consisting of a Zener diode and a resistor connected in series for narrowing down the base current of the oscillation transistor is connected to the second resistor circuit section in parallel to the second resistor circuit section for supplying the base current at startup. The third part consists of a resistor.
A resistor circuit section is connected, and the divided voltage output of the resistor of the first resistor circuit section is connected to the base of a protection transistor connected between the control input terminal of the control circuit and the emitter of the oscillation transistor. Connecting to a control input terminal of the circuit an output of a comparator amplifier that controls the control circuit by comparing a part of the output fed back from the output winding of the high voltage transformer with a reference voltage;
Each resistance value of the first resistor circuit section is set such that when the voltage of the regeneration capacitor increases as the oscillation of the oscillation transistor attenuates, the divided voltage output exceeds the on-voltage of the protection transistor, The Zener voltage of the Zener diode is
A self-oscillation type high-voltage power supply characterized by being set lower than the output voltage of the control circuit during normal oscillation.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57062249A JPS58179179A (en) | 1982-04-13 | 1982-04-13 | Self-oscillation type high voltage power source |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57062249A JPS58179179A (en) | 1982-04-13 | 1982-04-13 | Self-oscillation type high voltage power source |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS58179179A JPS58179179A (en) | 1983-10-20 |
| JPH0572191B2 true JPH0572191B2 (en) | 1993-10-08 |
Family
ID=13194674
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP57062249A Granted JPS58179179A (en) | 1982-04-13 | 1982-04-13 | Self-oscillation type high voltage power source |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS58179179A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61177397U (en) * | 1985-04-19 | 1986-11-05 |
-
1982
- 1982-04-13 JP JP57062249A patent/JPS58179179A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS58179179A (en) | 1983-10-20 |
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