DE102017220121A1 - Voltage limiting device and method of manufacturing a voltage limiting device - Google Patents

Abstract

The invention relates to a voltage limiting device having a first terminal (10) and a second terminal (12), between which an input voltage (U _in ) can be applied, a third terminal (14) and a fourth terminal (16), between which an output voltage ( U _out ), and a first bipolar transistor (18), a second bipolar transistor (20), a resistor (22) and a Zener diode (24), wherein an emitter of the first bipolar transistor (18) to the first terminal (10 ), a collector of the first bipolar transistor (18) to the third terminal (14), a collector of the second bipolar transistor (20) to a base of the first bipolar transistor (18), the first resistor (22) to an emitter of the second bipolar transistor (20 ) and at the fourth terminal (16), and the Zener diode (24) at the collector of the first bipolar transistor (18) and at the emitter of the second bipolar transistor (20) are electrically connected, and a reference voltage zw Is a base of the second bipolar transistor (20) and the second terminal (12) can be applied or applied.

Description

The invention relates to a voltage limiting device and a power supply. Likewise, the invention relates to a manufacturing method for a voltage limiting device.

State of the art

From the prior art are linear regulators, such as those in the DE 10 2014 016 037 A1 disclosed low energy switching linear regulator, known.

Disclosure of the invention

The invention provides a voltage limiting device having the features of claim 1, a power supply having the features of claim 8 and a manufacturing method for a voltage limiting device having the features of claim 10.

Advantages of the invention

The voltage limiting device according to the invention is suitable for reliably limiting / holding its output voltage within permissible values. The voltage limiting device according to the invention is also well suited for the indirect regulation of its output voltage at all operating points (such as during idling or at a maximum load). Despite its highly efficient operation, the voltage limiting device according to the invention is inexpensive and can be produced with a small space requirement. The voltage limiting device according to the invention can therefore be used in a versatile and advantageous manner.

In comparison with conventional linear regulators, a power loss of the voltage limiting device according to the invention is significantly reduced in all operating points. The power loss of the voltage limiting device according to the invention during its operation is therefore negligible. A cooling device is therefore not necessary for the voltage limiting device, whereby additional costs and energy can be saved.

In an advantageous embodiment, the voltage limiting device comprises a voltage divider device, which is electrically connected to the first connection and to the second connection such that the reference voltage can be applied by means of the voltage divider device between the base of the second bipolar transistor and the second connection. The reference voltage can thus be obtained in a simple manner by means of a division of the input voltage carried out by the voltage divider device.

For example, the voltage divider means may comprise a second resistor and a third resistor, the second resistor being electrically connected on its first side to the first terminal or to a fourth resistor attached to the first terminal and to the second branch at a first branch point and the third one Resistor on its first side at the first branch point and on its second side is electrically connected to the second terminal, and wherein the base of the second bipolar transistor is electrically connected at the first branch point. The voltage divider device is thus inexpensive and can be produced with a small space requirement. It should be noted, however, that a formability of the voltage divider device is not limited to the example described in this paragraph.

In a further advantageous embodiment, the voltage limiting device also comprises a voltage regulator device, which is electrically connected to the first connection and to the second connection in such a way that a voltage obtained from the input voltage can be stabilized by means of the voltage regulator device. The voltage regulator device can in particular be used to keep the voltage at the voltage divider constant.

In an inexpensive embodiment, the voltage regulator device comprises the fourth resistor and a second Zener diode, wherein the fourth resistor is electrically connected on its first side to the first terminal and on its second side to a second branch point and the second Zener diode whose reverse direction from its first side to its second side, is electrically connected on its first side to the second branch point and on its second side to the second terminal. However, an adaptability of the voltage regulator device is not limited to the example described in this paragraph.

In a further advantageous embodiment, the voltage limiting device is designed as a microelectrical component. A minimization of the voltage limiting device is therefore easy and possible by means of a comparatively low workload.

By way of example, the first bipolar transistor may be a pnp bipolar transistor and / or the second bipolar transistor may be an npn bipolar transistor. The bipolar transistor types listed here are inexpensive and little space-consuming semiconductor components.

The advantages described above are also met in a power supply unit with such a voltage limiting device. The power supply may be, for example, a computer power supply, a switched-mode power supply, a DCDC converter and / or a power supply for an inverter. The voltage limiting device according to the invention is thus versatile. Usability of the voltage limiting device according to the invention is not limited to the examples listed here.

Furthermore, carrying out a corresponding manufacturing method for a voltage limiting device also provides the advantages described above. It is expressly pointed out that the manufacturing method according to the above-explained embodiments of the voltage limiting device can be further developed.

list of figures

• 1 eine schematische Darstellung einer Ausführungsform der Spannungsbegrenzungsvorrichtung; und
• 2 ein Flussdiagramm zum Erläutern einer Ausführungsform des Herstellungsverfahrens für eine Spannungsbegrenzungsvorrichtung.

Further features and advantages of the present invention will be explained below with reference to the figures. Show it:

• 1 a schematic representation of an embodiment of the voltage limiting device; and
• 2 a flowchart for explaining an embodiment of the manufacturing method for a voltage limiting device.

Embodiments of the invention

1 shows a schematic representation of an embodiment of the voltage limiting device.

In the 1 schematically illustrated voltage limiting device may also be referred to as a voltage limiting circuit. By means of the voltage limiting device, a provided input voltage U _in in an output voltage U _out Be "converted", wherein the voltage limiting device, the output voltage U _out to a (predetermined) maximum value Uout-max of the output voltage U _out (within permissible tolerances).

The voltage limiting device has a first connection 10 and a second connection 12 on, between which the input voltage U _in can be applied / created. In addition, the voltage limiting device has a third connection 14 and a fourth connection 16 , between which the output voltage U _out can be tapped / tapped. The second connection 12 and / or the fourth port 16 may in particular be grounded. The voltage limiting device comprises at least a first bipolar transistor 18 , a second bipolar transistor 20 , a first resistance 22 and a first Zener diode (zener diode) 24 , The first bipolar transistor 18 is preferably a pnp bipolar transistor. An emitter of the first bipolar transistor 18 is at the first connection 10 electrically connected. In addition, a collector of the first bipolar transistor 18 to the third port 14 electrically connected. Furthermore, a collector of the second bipolar transistor 20 to a base of the first bipolar transistor 18 electrically connected.

The second bipolar transistor 20 is preferably an npn bipolar transistor. An emitter of the second bipolar transistor 20 is at the first resistance 22 electrically connected. In addition, a reference voltage (not shown) is provided between a base of the second bipolar transistor 20 and the second port 12 Equipped / applied. The reference voltage can be understood as an externally supplied voltage. However, as will be explained in more detail below, the reference voltage can also be easily divided by dividing the input voltage U _in be won.

During the first resistance 22 from its first side to the emitter of the second bipolar transistor 20 electrically connected, is the first resistor 22 on its second side at the fourth port 16 electrically connected. The first Z-diode 24 has a reverse direction, which from its first side, to which the first Zener diode 24 at the collector of the first bipolar transistor 18 (and at the third port 14 ) is electrically connected, to its second side, to which the first Zener diode 24 at the emitter of the second bipolar transistor 20 (and on the first page of the first resistance 22 ) is electrically connected, is aligned. As in 1 shown schematically, a branch point 26 between the collector of the first bipolar transistor 18 , the third connection 14 and the first side of the Zener diode 24 be educated. Another branch point 28 may be between the emitter of the second bipolar transistor 20 , the second side of the Zener diode 24 and the first resistance 22 be educated. In addition, there may be a branch point 30 between the second port 12 , the fourth connection 16 and the second side of the first resistor 22 lie.

As an optional further development, the voltage limiting device also has a voltage divider device 32 and 34 which are so at the first port 10 and at the second port 12 electrically connected is that the Reference voltage by means of the voltage divider device 32 and 34 between the base of the second bipolar transistor 20 and the second port 12 can be applied. In the example of 1 has the voltage divider device 32 and 34 a second resistor 32 and a third resistor 34 on. The second resistance 32 is on his first page at the first port 10 (or at one at the first port 10 Tied fourth resistance 36 ) electrically connected. On its second side is the second resistance 32 a branch point 38 electrically connected, on which also a first side of the third resistor 34 electrically connected. The second side of the third resistance 34 is at the second port 12 , (or at one between the second port 12 and the fourth port 16 / the branch point 30 trained branch point 40 ) electrically connected. By means of the voltage divider device 32 and 34 can the input voltage U _in be divided into the reference voltage, which subsequently, since the base of the second bipolar transistor 20 at the branch point 38 electrically connected to the second bipolar transistor 20 is available.

As a further optional supplement, the voltage limiting device can still be a voltage regulator device 36 and 42 have, which at the first terminal 10 and at the second port 12 electrically connected is that a voltage at a branching point / node 46 by means of the voltage regulator device 36 and 42 is stabilizable. By way of example, the voltage regulator device comprises 36 and 42 in the embodiment of the 1 the fourth resistance 36 and a second zener diode (zener diode) 42 , The fourth resistance 36 is on his first page at the first port 10 (or at one between the first port 10 and the emitter of the first bipolar transistor 18 trained branch point 44 ) electrically connected. The second side of the fourth resistor 36 is at the branch point 46 electrically connected, on which also the second Zener diode 42 electrically connected. A reverse direction of the second Zener diode 42 is from her first page, on which the second zener diode 42 at the branch point 46 electrically connected, to its second side, on which the second Zener diode 42 at the second port 12 (or one between the second port 12 and the fourth port 16 / the branch point 30 or 40 lying branch point 48 ) is electrically connected, aligned. A breakdown voltage of the second Zener diode 42 is smaller than the input voltage U _in . A concern of the input voltage U _in between the first connection 10 and the second port 12 thus causes a current flow through the fourth resistor 36 and the second Zener diode 42 wherein the second Zener diode is for keeping the voltage at the branch point constant 46 ( "Node voltage 46 ").

When with the voltage divider device 32 and 34 trained voltage limiting device of 1 is the second resistance 32 on its first page at the branch point 46 electrically connected. The means of the voltage regulator device 36 and 42 stabilized stress at the branch point 46 ( "Node voltage 46 ") Is thus connected to the voltage divider device 32 and 34 provided.

Hereinafter, an operation of the voltage limiting device of 1 more detail:

The from the between the first connection 10 and the second port 12 applied input voltage U _in gained voltage at the branch point / node 46 is by means of the voltage divider device 32 and 34 for generating the reference voltage "divided". (During the division of the voltage at the branch point 46 by means of the voltage divider device 32 and 34 is a "voltage drop" at the third resistor 34 constant, so that the reference voltage can be reliably maintained.)

The generated reference voltage is applied as the base voltage of the second bipolar transistor, so that a base current through the second bipolar transistor 20 flows. The base current through the second bipolar transistor 20 solves a collector current through the second bipolar transistor 20 out. The collector current through the second bipolar transistor 20 however, is at the same time a base current of the first bipolar transistor 18 , In summary, the base current dissipates through the second bipolar transistor 20 Therefore, a collector current of the first bipolar transistor 18 which is at the same time an output or load current of the voltage limiting device.

wobei U₂₂ durch den ersten Widerstand 22 definiert ist und U₂₄ eine Durchbruchspannung der ersten Z-Diode 24 ist. Der Maximalwert Uout-max der Ausgangsspannung U_out kann somit stufenlos eingestellt werden.The application of the input voltage U _in between the first connection 10 and the second port 12 thus causes an increase in between the third port 14 and the fourth connection 16 tapped output voltage U _out until the predetermined maximum value Uout-max of the output voltage U _out is reached. For the maximum value Uout-max of the output voltage U _out Equation (Eq.1) holds with: $${\text{U}}_{\text{out}-\text{Max}}={\text{<figure-callout id="22" label="U" filenames="DE102017220121A1\_0002.png" state="{{state}}">U</figure-callout>}}_{22}+{\text{<figure-callout id="24" label="U" filenames="DE102017220121A1\_0002.png" state="{{state}}">U</figure-callout>}}_{24}.$$

where U ₂₂ through the first resistor 22 is defined and U _{24 is} a breakdown voltage of the first Zener diode 24 is. The maximum value Uout-max of the output voltage U _out can thus be adjusted continuously.

Reaches the output voltage U _out its maximum value U _out-max , then the first Z-diode 24 conductive and a current flows through the first Zener diode 24 and the first resistance 22 , The flow of current through the first resistor 22 triggers a voltage drop U ₂₂ at the first resistor 22 from, which is an emitter voltage of the second bipolar transistor 20 grow up. This triggers a reduction of the base current through the second bipolar transistor 20 from, because the base voltage of the second bipolar transistor through the second Zener diode 42 is kept constant. The second bipolar transistor 20 Therefore, begins to block, which also the base current of the first bipolar transistor 18 reduced. This triggers a blocking of the first bipolar transistor 18 out, reducing the output voltage U _out is limited to its maximum value Uout-max.

A loading of the output voltage U _out solves a reduction of the output voltage U _out out, and through the first Zener diode 24 and the first resistance 22 flowing electricity gets smaller. The first bipolar transistor 18 therefore becomes more conductive and tries the output voltage U _out to keep constant.

Falls the output voltage U _out below its maximum value U _out-max , no current flows through the first Zener diode 24 , This triggers a reduction of the loss voltage U ₂₂ and the first bipolar transistor 18 and the second bipolar transistor 20 switch on. The output voltage U _out thus quickly grows back to its maximum value Uout-max.

It is also noted that the output voltage U _out even at a maximum output power (or at a maximum output or load current) remains limited to its maximum value Uout-max (within permissible tolerances).

The voltage limiting device of 1 is thus a very cost effective and efficient circuit for limiting the output voltage U _out to the maximum value Uout-max (within permissible tolerances). An operating power dissipation occurring during operation is negligible. The voltage limiting device must therefore not be cooled during its operation. It is therefore possible to dispense with forming a cooling device on the voltage limiting device.

A temperature influence of the voltage limiting device can even by a suitable choice of the first resistor 22 be partially compensated, since a change in temperature through the first resistor 22 flowing stream affected. The one at the first resistance 22 occurring voltage drop U ₂₂ thus counteracts the effect of temperature.

The voltage limiting device of 1 can be easily formed as a microelectrical component. This facilitates a cost-effective production of the voltage limiting device, as well as their minimization.

The voltage limiting device has a high efficiency (both at idle and rated load). The output voltage U _out remains within any given operating point of the voltage limiting device within a given specification.

The voltage limiting device can be used for all products / devices with indirectly regulated voltage supply. For example, the voltage limiting device for a power supply / auxiliary power supply of a computer power supply or a switching power supply, such as in particular a DCDC converter or a (machine) inverter, can be used advantageously.

A power supply unit with the voltage limiting device described above (as a subunit installed on the power supply) also brings about the stated advantages. The power supply may be e.g. a computer power supply, a switching power supply, a DCDC converter and / or a power supply for an inverter.

2 FIG. 12 is a flowchart for explaining an embodiment of the manufacturing method for a voltage limiting device. FIG.

In one process step S1 a first terminal and a second terminal are formed such that an input voltage can be applied between the first terminal and the second terminal. In addition, a third terminal and a fourth terminal are formed such that an output voltage can be tapped between the third terminal and the fourth terminal.

In one process step S2 the (later) voltage limiting device is formed with a first bipolar transistor, wherein an emitter of the first bipolar transistor to the first terminal and a collector of the first bipolar transistor are electrically connected to the third terminal. As a process step S2 the (later) voltage limiting device is also formed with a second bipolar transistor such that a reference voltage obtained by dividing the input voltage or provided externally between a base of the second bipolar transistor and the second terminal can be applied / applied. In addition, a collector of the second Bipolar transistor to a base of the first bipolar transistor and a resistor (on its first side) to an emitter of the second bipolar transistor electrically connected. The resistor is electrically connected (on its second side) to the fourth terminal.

In a further process step S4 a Zener diode of the (later) voltage limiting device, whose reverse direction is aligned from its first side to its second side, electrically connected on its first side to the collector of the first bipolar transistor and on its second side to the emitter of the second bipolar transistor.

The voltage limiting device obtained by means of the manufacturing method described here has all the advantages already described above. The process steps S1 to S4 can be executed in any chronological order and at least partially simultaneously. In addition, the manufacturing method described here according to the above-described voltage limiting device can be further developed.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102014016037 A1 [0002]

Claims (10)

A voltage limiting device comprising: a first terminal (10) and a second terminal (12), between which an input voltage (U _in ) can be applied; a third terminal (14) and a fourth terminal (16), between which an output voltage (U _out ) can be tapped off; and at least a first resistor (22) and a first bipolar transistor (18); characterized in that an emitter of the first bipolar transistor (18) is electrically connected to the first terminal (10) and a collector of the first bipolar transistor (18) is electrically connected to the third terminal (14); the voltage limiting device comprises a second bipolar transistor (20), a collector of the second bipolar transistor (20) being electrically connected to a base of the first bipolar transistor (18) and a reference voltage between a base of the second bipolar transistor (20) and the second terminal (12) can be applied or is applied; the first resistor (22) is electrically connected on its first side to an emitter of the second bipolar transistor (20) and on its second side to the fourth terminal (16); and the voltage limiting device comprises a first Zener diode (24) whose reverse direction is aligned from its first side to its second side and which on its first side to the collector of the first bipolar transistor (18) and on its second side to the emitter of the second Bipolar transistor (20) is electrically connected. Voltage limiting device according to Claim 1 wherein the voltage limiting device comprises voltage divider means (32, 34) electrically connected to the first terminal (10) and the second terminal (12) such that the reference voltage is connected between the base of the second one by means of the voltage divider means (32, 34) Bipolar transistor (20) and the second terminal (12) can be applied. Voltage limiting device according to Claim 2 wherein the voltage divider means (32, 34) comprises a second resistor (32) and a third resistor (34), the second resistor (32) on its first side at the first terminal (10) or at the first terminal (10). 10), and on its second side at a first branch point (38), and the third resistor (34) on its first side at the first branch point (38) and on its second side at the second port (12) is electrically connected, and wherein the base of the second bipolar transistor (20) at the first branch point (38) is electrically connected. Voltage limiting device according to one of the preceding claims, wherein the voltage limiting device comprises a voltage regulator means (36, 42) which is so electrically connected to the first terminal (10) and the second terminal (12) that one of the input voltage (U _in ) won Voltage by the voltage regulator means (36, 42) is stabilized. Voltage limiting device according to Claim 4 wherein the voltage regulator means (36, 42) comprises the fourth resistor (36) and a second Zener diode (42), the fourth resistor (36) on its first side at the first terminal (10) and on its second side a second branch point (46) is electrically connected and the second Zener diode (42) whose reverse direction is aligned from its first side to its second side, on its first side at the second branch point (46) and on its second side on the second terminal (12) is electrically connected. Voltage limiting device according to one of the preceding claims, wherein the voltage limiting device is designed as a microelectrical component. Voltage limiting device according to one of the preceding claims, wherein the first bipolar transistor (18) is a pnp bipolar transistor and / or the second bipolar transistor (20) is an npn bipolar transistor. Power supply with a voltage limiting device according to one of the preceding claims. Power supply after Claim 8 , wherein the power supply is a computer power supply, a switching power supply, a DCDC converter and / or a power supply for an inverter. Manufacturing method for a voltage limiting device comprising the steps of: forming a first terminal (10) and a second terminal (12) such that an input voltage (U _in ) can be applied between the first terminal (10) and the second terminal (S1) (S1) ; Forming a third terminal (14) and a fourth terminal (16) such that between the third terminal (14) and the fourth terminal (16) an output voltage (U _out ) can be tapped off; and forming the voltage limiting device at least with a resistor (22) and a first bipolar transistor (18); characterized by the steps of: electrically connecting an emitter of the first bipolar transistor (18) to the first terminal (10) and a collector of the first bipolar transistor (18) to the third terminal (14) (S2); Forming the voltage limiting device with a second bipolar transistor (20) such that a reference voltage obtained by division of the input voltage (U _in ) or provided externally between a base of the second bipolar transistor (20) and the second terminal (12) can be applied (S3); Electrically connecting a collector of the second bipolar transistor (20) to a base of the first bipolar transistor (18); Electrically connecting the resistor (22) on its first side to an emitter of the second bipolar transistor (20) and on its second side to the fourth terminal (16); and electrically connecting a Zener diode (24) whose reverse direction is aligned from its first side to its second side, on its first side to the collector of the first bipolar transistor (18) and on its second side to the emitter of the second bipolar transistor (20 ) (S4).

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