WO1998058302A1

WO1998058302A1 - Regulating device

Info

Publication number: WO1998058302A1
Application number: PCT/DE1998/001420
Authority: WO
Inventors: Frank-Lothar Schwertlein; Michael Lenz
Original assignee: Siemens Aktiengesellschaft
Priority date: 1997-06-18
Filing date: 1998-05-25
Publication date: 1998-12-23
Also published as: EP0990199B1; JP2002501648A; DE59802077D1; JP3425961B2; EP0990199A1

Abstract

The invention relates to a regulating device, comprising a first controllable semiconductor component (3) with an input terminal (4) connected to the regulator input (1), an output terminal (5) connected to the regulator output (2) and a control terminal (6); a second semiconductor component (20) connected to the control terminal (6) of the first semiconductor component (3), which second component has an input terminal (21), an output terminal (23) and a control terminal (22); a comparator device (25) having a first input (27), a second input (28) and an output (26) connected to the control terminal (22) of the second semiconductor element (20), whereby a reference voltage (Vref) can be fed to the first input (27) and the second input (28) is connected to the regulator output (2); and a driver device (40), which partly diverts the current from the control terminal (6) of the first semiconductor component (3) to the regulator output (2) by means of an input signal emitted at the level of the regulator input (1) when a predefined limit value (Vg) is exceeded.

Description

description

Regulator device

The invention relates to a regulator device, and in particular to a regulator device with a Darlington structure with low residual voltage for regulators with a very low voltage drop.

Controllers serve to stabilize a setpoint, for example an output voltage or an output current. An actuator, which is usually a (power) semiconductor component in the form of a transistor, is influenced by a manipulated variable which can be seen from the difference between an actual value, e.g. a certain fraction of the output voltage or current, and the setpoint, e.g. in the form of a reference voltage.

Depending on the arrangement of the actuator, continuous controllers can be designed as series or series controllers or as parallel controllers. Series controllers are used much more frequently in practice than parallel controllers. With series control or series stabilization, the actuator lies in series with the load, while with parallel control or parallel stabilization it lies in parallel with the load. Parallel controllers have a lower efficiency than series controllers, since they also consume full power when idle. Another disadvantage of parallel regulators compared to series regulators is that the transistor used as an actuator must absorb the full output voltage.

Fig. 1 shows the basic structure of a conventional continuous series controller. The controller has an input I and an output Q. Between the input I and the output Q there is a first controllable semiconductor component T1 as an actuator switched in the form of a pnp transistor, the emitter El is connected to the input I and the collector Cl to the output Q. The control or base connection B1 of the semiconductor component T1 is connected to the collector C2 of a second semiconductor component T2. The second semiconductor component T2 is complementary to the first semiconductor component T1 and is designed as an npn transistor. The emitter E2 of the second semiconductor component T2 is connected to ground M. The control or base connection B2 of the second semiconductor component T2 is connected to the output of a comparison circuit in the form of an operational amplifier Op, which compares a setpoint reference voltage Vref present at a first input (+) with an actual value voltage which is between a Resistor R1 and a resistor R2 of a voltage divider is tapped. Through the voltage divider R1, R2, part of the voltage present at the output Q is fed back as an actual value to the second input (-) of the comparison circuit, the comparison circuit comparing the feedback actual value with the target value, ie the reference voltage present at the second input (+), and outputs a corresponding control signal to the control connection B2 of the second semiconductor component T2. The second semiconductor component T2 serves as a driver and, depending on the difference signal at the two inputs of the comparison circuit Op, amplifies the control current at the control or base connection of the first semiconductor component T1.

This stabilizes the output voltage VQ at the output Q of the controller depending on the reference voltage Vref and the resistors Rl, R2:

VQ = Vref * (Rl + R2) / R2

In the controller shown in FIG. 1, which is manufactured on a bipolar basis, a pnp transistor is used as the first semiconductor component. element T1 used. This is usually constructed as a lateral pnp transistor, that is to say as a bipolar transistor, in which the emitter, base and collector are arranged horizontally or laterally and the effect current flows from the emitter to the collector in the lateral direction along the surface of a substrate.

Such lateral pnp transistors are usually manufactured using a double ISO PNP technology DOPL.

However, the lateral pnp transistors have a relatively low current gain, which has the consequence that the control current of the first semiconductor component T1 serving as an actuator causes high power losses, in particular at high input voltages. The poor efficiency and the associated high power losses make it necessary to provide such controllers for cooling with power housings. The necessary power housings are expensive and require considerable space, which prevents miniaturization of the regulator circuit.

To avoid these disadvantages, vertical pnp transistors have recently been used instead of lateral structures for the first semiconductor component T1. In particular at higher currents, these have significantly higher current gains than lateral pnp transistors.

The use of Darlington structures is due to the excessive drop or drop voltage, i.e. the voltage difference between the emitter and the collector of the Darlington transistor is not practiced.

A disadvantage of using vertical pnp transistors is that a Most intensive process is necessary, which is about 20-30% more expensive than the manufacturing process for lateral pnp transistors. In addition, vertical pnp transistors are considerably more sensitive to environmental influences, for example ESD influences, and less robust than lateral pnp transistors.

It is therefore the object of the invention to create a controller device which has a low power loss, is robust and can be produced inexpensively.

According to the invention, this object is achieved by the controller device defined in claim 1, that is to say by a controller device having a first controllable semiconductor component which has an input connection connected to the controller input, an output connection connected to the controller output and a control connection; a second semiconductor component connected to the control connection of the first semiconductor component and having an input connection, an output connection and a control connection; a comparison device which has a first input, a second input and an output connected to the control connection of the second semiconductor component; wherein a reference voltage can be applied to the first input and the second input is connected to the controller output; and a driver device which, when a predetermined threshold value is exceeded by an input signal present at the controller input, partially derives the current from the control connection of the first semiconductor component to the controller output.

The invention is based on the idea of operating the first semiconductor component as a Darlington structure from a predetermined limit voltage or threshold voltage present at the regulator input, and thus the current amplification and the efficiency the controller significantly.

Preferred developments of the regulator device according to the invention are specified in the subclaims.

According to a preferred development, the driver device has a current mirror circuit. This has the particular advantage that the current gain is limited to values at which the control loop operates stably.

According to a further preferred development, the current mirror circuit has a third and a fourth controllable semiconductor component, the first main connections of which are connected to one another and to the control connection of the first semiconductor component and the control connections of which are connected to one another, the second main connection of the third semiconductor component being connected to the controller output and the second main connection of the fourth semiconductor component is connected to the one main connection of the second semiconductor component.

According to a further preferred development, an inverse current blocking device is connected between the output connection of the first controllable semiconductor component and the current mirror circuit. This offers the particular advantage that an inverse operation of the current mirror circuit with low and negative input voltage at the regulator input is prevented and a switchover from Darlington operation of the first controllable semiconductor component to normal operation is made possible.

According to a further preferred development, the inverse current blocking device is designed as a diode. This offers the particular advantage of easy integration with the other semiconductor structures. According to a further preferred development, the connected control connections of the current mirror circuit are connected to the control connection of the first semiconductor component and to the one main connection of the second semiconductor component.

According to a further development, a resistor or an active current source is connected between the connected control connections of the current mirror circuit and the control connection of the first semiconductor component.

According to a further preferred development, a resistor or an active current source is connected between the control connection of the first semiconductor component and the regulator input.

According to a further preferred development, the first semiconductor component is a lateral pnp transistor.

According to a further preferred development, the two semiconductor components of the current mirror circuit are designed as pnp transistors and the second semiconductor component as an npn transistor.

According to a further preferred development, the comparison device is a differential amplifier.

According to a further preferred development, the differential amplifier is an operational amplifier.

According to a further preferred development, the first input of the comparison device is connected to the controller output via a voltage divider. According to a further preferred development, the reference voltage is adjustable.

The invention is explained in more detail below on the basis of preferred embodiments with reference to the accompanying drawings.

Show it:

Figure 1 shows the structure of a conventional continuous serial controller.

2 shows the structure of a preferred embodiment of the controller according to the invention; and

3 shows the power losses of the known continuous serial controller according to FIG. 1 and the controller according to the invention as a function of the voltage present at the controller input.

2 shows the structure of a preferred embodiment of the controller according to the invention. The controller has a controller input 1 and a controller output 2. A controllable semiconductor component 3 is connected between the controller input 1 and the controller output 2. The first controllable semiconductor component 3 shown in FIG. 2 is a bipolar lateral pnp transistor. The first semiconductor component 3 has an input connection 4, which is connected to the controller input 1, and an output connection 5, which is connected to the controller output 2. The semiconductor component 3 is controlled by a control connection 6. The control connection 6 is the base connection, the input connection 4 is the emitter and the output connection is the collector of this pnp transistor 3. A driver circuit 40 in the form of a current mirror circuit 7 is connected to the control connection 6 of the second semiconductor component 3 and is formed by a third controllable semiconductor component 8 and a fourth controllable semiconductor component 12. The third semiconductor component 8 has a control connection 9, an input connection 10 and an output connection 11. The fourth semiconductor component 12 has a control connection 13, an input connection 14 and an output connection 15. The control connections 9, 13 of the third semiconductor component 8 and of the fourth semiconductor component 12 are connected to one another at a node 16. The third and fourth semiconductor components 8, 12 are each formed by a pnp transistor. The control connections 9, 13 each form the base connections, the input connections 10, 14 each the emitter connections and the output connections 11, 15 each the collector connections of the pnp transistors 8, 12.

The control connection 6 of the first semiconductor component 3 is connected to the controller input 1 and the input connection 4 of the first semiconductor component 3 via a resistor or an active current source 17. The control connection 6 is also connected via a resistor or an active current source 18 to the node 16 and directly to the input connections 10, 14 of the third and fourth semiconductor components 8, 12 of the current mirror circuit 7.

The output connection 11 is connected to an inverse current blocking device 19, which is designed as a diode. The anode of the diode 19 is connected to the output terminal 11, ie the collector of the third semiconductor component 8, and the cathode of the diode 19 is connected to the output terminal 5, ie the collector of the lateral pnp transistor 3, and to the regulator output 2. The inverse current blocking device 19 prevents the third semiconductor component 8 from operating inversely with low or negative input voltages at controller input 1 and enables switching from Darlington operation of the controller to normal operation.

The output terminal 15 of the fourth semiconductor component 12 and the node 16 of the current mirror circuit 7 are connected to the input terminal 21 of the second semiconductor component 20. In addition to the input connection 21, the second semiconductor component 20 has a control connection 22 and an output connection 23.

The second semiconductor component 20 is designed as a bipolar npn transistor and is complementary to the first semiconductor component 3. The input terminal 21 is formed by the collector, the control terminal 22 by the base and the output terminal 23 by the emitter of the bipolar npn transistor. The output terminal 23 is grounded.

The input terminal 22 of the second semiconductor component 20 is connected via a drive line 24 to the output 26 of a comparison circuit 25, which is formed by an operational amplifier. The comparison circuit 25 has a first non-inverting input 27 (+) and a second inverting input 28 (-), a reference voltage Vref being present at the first input 27 and the second input 28 being connected via a feedback line 29 to a tapping node 31 of a voltage divider 30 is. The tap node 31 lies between two resistors 32, 33 connected in series, the voltage divider resistor 33 being connected between the tap node 31 and ground and the voltage divider resistor 32 being arranged between the tap point 31 and the controller output 2. The voltage divider 30 feeds back part of the voltage present at the controller output 2 via the feedback line 29 to the second input 28 of the comparison circuit 25.

The comparison circuit 25, which is designed as a differential amplifier, compares the feedback actual voltage value with a reference or reference applied to the first input 27. Target voltage value and controls the control connection 22 of the second semiconductor component 20 as a function of the voltage difference between the inputs 27, 28 via the control line 24. The second semiconductor component 20 works as a current amplifier or driver and controls the base current at the control connection 6 of the first semiconductor component 3 as a function of the voltage difference between the reference voltage Vref and the tapped and fed-back output voltage of the regulator.

The current mirror circuit 7 generates a constant current from a reference current and limits the current gain to values at which the control loop operates stably.

If the input voltage Vi present at the controller input 1 exceeds a predetermined threshold value or a predetermined limit voltage Vg, part of the current present at the control connection 6 of the first semiconductor component is directly turned on by the driver device 40 arranged between the first semiconductor component 3 and the second semiconductor component 20 Controller output 2 directed. After the limit voltage Vg has been exceeded, the first semiconductor component 3 switches from normal operation to Darlington operation and, together with the third semiconductor component 8, forms a Darlington circuit consisting of two transistors. This increases the total current gain. The power loss Pv in the second controllable semiconductor component 20 is considerably reduced in the case of input voltages which are above the limit voltage Vg, in comparison to a conventional regulator according to the prior art. In this way, the need for a complex and space-consuming cooling device or for a power housing on the controller according to the invention is eliminated.

Fig. 3 shows the power loss curve of a conventional controller and a controller according to the invention in comparison. The power loss Pv, which is determined by the product of the input voltage Vi and the current strength at the control terminal 6 of the lateral pnp transistor in FIG. 3 or of the transistor Tl in FIG. 1, increases with the conventional regulator (I) with increasing input voltage Vi linear on. In the controller (II) according to the invention, the power loss also increases linearly up to a limit voltage Vg. When the limit voltage Vg is reached, the controller according to the invention switches from normal operation to Darlington operation, the required base current and thus the power loss initially decrease sharply and increase linearly with a further increase in input voltage Vi but with a smaller gradient than in the conventional controller.

The invention is not limited to the described embodiment, but can be modified in many ways within the scope of the protection of the following claims. For example, the bipolar transistors shown in FIG. 2 can be replaced by field effect transistors or other controllable semiconductor components. Furthermore, the structure of the controller can be complementary to the structure shown in FIG. 2, ie the first, third and fourth semiconductor components 3, 8, 12 are formed by npn transistors and the second semiconductor component 20 by an npn transistor. The reference voltage Vref is Ren embodiment adjustable. Finally, the driver circuit 40 is not limited to a current mirror circuit, but can be formed by any suitable active or passive driver circuit.

Claims

claims

1. Controller device with:

a first controllable semiconductor component (3) which has an input connection (4) connected to the controller input (1) and an output connection connected to the controller output (2)

(5) and has a control connection (6);

a second semiconductor component (20) connected to the control connection (6) of the first semiconductor component (3) and having an input connection (21), an output connection (23) and a control connection (22);

a comparison device (25) having a first input (27), a second input (28) and an output (26) connected to the control connection (22) of the second semiconductor component (20);

wherein a reference voltage (Vref) can be applied to the first input (27) and the second input (28) is connected to the controller output (2); and

a driver device (40) which, when a predetermined threshold value (Vg) is exceeded by an input signal present at the controller input (1), transfers the current from the control connection

(6) of the first semiconductor component (3) partially to the controller output (2).

2. Controller device according to claim 1, characterized in that the driver device (40) has a current mirror circuit

(7).

3. Controller device according to claim 2, characterized in that the current mirror circuit (7) a third and a fourth Controllable semiconductor component (8, 12), the first main connections (10, 14) of which are connected to one another and to the control connection (6) of the first semiconductor component (3) and whose control connections (9, 13) are connected to one another, the second main connection ( 11) of the third semiconductor component (8) with the controller output (2) and the second main connection (15) of the fourth semiconductor component (12) with the one main connection (21) of the second semiconductor component (20).

4. Control device according to one of the preceding claims, characterized in that an inverse current blocking device (19) is connected between the output terminal (5) of the first semiconductor component (3) and the current mirror circuit (7).

5. Controller device according to claim 4, characterized in that the inverse current blocking device (19) is a diode.

6. Controller device according to one of claims 3 to 5, characterized in that the connected control connections (9, 13) to the control connection (6) of the first semiconductor component (3) and to the one main connection (21) of the second semiconductor component (20) are.

7. Controller device according to one of the preceding claims 3 to 6, characterized in that a resistor (18) or an active current source is connected between the control connections (9, 13) and the control connection (6) of the first semiconductor component (3).

8. Controller device according to one of the preceding claims, characterized in that between the control connection (6) of the first semiconductor component (3) and the controller input (1) a resistor (17) or an active current source is switched.

9. Controller device according to one of the preceding claims, characterized in that the first semiconductor component

(3) is a lateral pnp transistor or a DMOS transistor.

10. Controller device according to one of the preceding claims 3 to 9, characterized in that the two semiconductor components (8, 12) of the current mirror circuit (7) pnp transistors and the second semiconductor component (20) is an npn transistor.

11. Controller device according to one of the preceding claims, characterized in that the comparison device

(25) is a differential amplifier.

12. Controller device according to claim 11, characterized in that the differential amplifier is an operational amplifier.

13. Controller device according to one of the preceding claims, characterized in that the second input (28) of the comparison device via a voltage divider (30) is connected to the controller output (2).

14. Controller device according to one of the preceding claims, characterized in that the reference voltage is adjustable.