WO2019158518A1

WO2019158518A1 - Circuit for distance determination and vehicle

Info

Publication number: WO2019158518A1
Application number: PCT/EP2019/053410
Authority: WO
Inventors: Thomas Bellingrath; Wolfgang Heinrich
Original assignee: Thomas Bellingrath
Priority date: 2018-02-16
Filing date: 2019-02-12
Publication date: 2019-08-22
Also published as: DE102018103518B3

Abstract

The invention relates to a circuit for activating a potential-free amplifying or switching element, which circuit comprises a voltage source (V0), a first diode (D1) and a load output for the connection of a load (ZL). An anode of the first diode (D1) is connected to a reference potential, and a first side of the current source and the first pin of the load output are connected to a cathode of the first diode (D1). A second pin of the load output is connected to a cathode of the second diode (D2), and an anode of the second diode (D2) is connected to a second side of the current source. An impedance (ZT) connects the cathode of the first diode (D1) to the cathode of the second diode (D2). The circuit comprises a second diode (D2) and a spur line (TL), which connects the cathode of the first diode (D1) to the anode of the second diode (D2). The spur line (TL) is formed and/or arranged such that common-mode reflections in the spur line are prevented, damped or suppressed.

Description

Circuit, distance determination system and a vehicle

The present invention relates to a circuit, a distance determining system and a vehicle.

In vehicles, systems are often used to determine the distance, which include a laser and, for the pulsed driving of the laser, a pulse amplifier driver. To the

Driving a potential-free amplifier or switching element, for example in switching power amplifiers at high operating voltage in technologies without complementary transistors, pulse amplifiers often include special circuits.

In the prior art circuits are often used, in which the switching off of a holding current leads to the Aufsteuern a pulse amplifier driver transistor. Figure 1 shows such a circuit according to the prior art.

The circuit comprises a voltage source VO, a diode D1 and a load output for connecting a load ZL. An anode of the diode D1 is connected to a first side of the voltage source VO. The load output is connected to a cathode of the diode D1 via a capacitor CBT. The circuit comprises a bootstrapping resistor RBT and a transistor T 1 which serves as a pulse amplifier driver transistor and whose source is connected to the load output. The bootstrapping resistor RBT thereby connects the cathode of the diode D1 with a gate of the transistor T1. A second terminal of the voltage source VO is connected to the drain of the transistor T1.

Between the gate of the transistor T1 and ground or lower voltage, a holding current is lin drawable. Between the load output and ground, an output voltage is removable.

The holding current lin must be so large that at least the required for safe shutdown of the transistor T1 voltage swing is achieved at the resistor RBT, on the other hand, the resistor RBT must be small enough to reach the necessary switching speed when switching on. In the case of fast pulse amplifiers for pulses with a small duty cycle, as required for example for laser drivers, this leads to the fact that a continuous current is necessary to keep the pulse amplifier driver switched off. Due to switching speed specifications, this current must be in some cases so large that it contributes significantly to the power loss of the overall circuit. According to the invention, a circuit with potential-free output for driving a potential-free amplifier or switching element is proposed. Furthermore, according to the invention, a pulse amplifier driver with the circuit according to the invention, a bodybuilder for pulse amplifier circuits, a driver circuit, a system with a laser and / or a bodybuilder and a vehicle according to the system according to the invention are proposed.

The circuit comprises a pulsed current source, a first diode and a load output for connecting a load, wherein an anode of the first diode with a

Reference potential and the first side of the power source and the first pin of the load output are connected to a cathode of the first diode. The circuit comprises a second diode, wherein a second pin of the load output is connected to a cathode of the second diode and an anode of the second diode is connected to a second side of the current source. An impedance connects the cathode of the first diode to the cathode of the second diode. The circuit further includes a stub that connects the cathode of the first diode to the anode of the second diode, wherein the stub is configured and / or arranged to prevent, attenuate, or suppress common mode reflections in the stub line to prevent the stub Reference potential for the running inside the stub electromagnetic wave can be varied without

Wave propagation in common mode of the two signal conductors of the stub line together leads to ground by reflection at the end of the stub line to interference.

Implementation examples for common mode rejection stubs are given in the exemplary embodiments.

The stub itself has a short circuit at the far end of the circuit

Low-impedance termination, at which the input signal of the stub line is reflected voltage-inverted. Thus, the drive can namely be inverted to avoid a quiescent current for the circuit.

Thus, according to the invention, a current flow in the drive is required only for the duration of the output pulse, so that in particular with a small duty cycle of the

Output voltage significant power loss can be saved.

In a preferred embodiment, the amplifier or switching element comprises at least one transistor, wherein the load output is connected to a source terminal of the at least one transistor, wherein a drain of the transistor with the second Side of the voltage source and a gate of the transistor is connected to the cathode of the second diode.

The amplifier or switching element may have two input terminals and two

Output terminals include, with the input side potential-free and the

Reference potential of the input side is determined by the output voltage. One of the load outputs can be connected to one of the input connections via a feedback path.

The feedback path may include: a conductive connection, a capacitor, or other combination of devices that transmits a high bandwidth output potential change to the input, particularly one or more source follower stages.

At the end the stub line is low-resistance or short-circuited. The reference or phase conductor potential in the application is varied to match the signal reflected at the short or under termination after returning to the

Stub line input to implement a floating voltage source, which represents functional negative impedance with delay by the reflection at the short-circuit end.

Common mode rejection may be accomplished, for example, by winding or folding the low capacitance stub of the outside of the outer conductor as a bulked element to ground, designing a high common mode impedance of the stub to ground, suppressing common mode excitation by ferrite bead at the circuit-side end of the spur line or implementation of the spur line as an inner part of a line type with third screen conductor, eg Triax or Twinax, where the common mode waveguide with an impedance close to the

Characteristic impedance is completed.

To implement the outer side of the outer conductor as a concentrated element with respect to ground, the stub line can be wound or folded such that a longest electrically effective outer dimension of the stub line is small compared to the inner line length of the stub line.

Additionally or alternatively, the energy contained in the common mode with respect to ground can be reduced by high-impedance design of the common mode with respect to ground.

The stub may in particular comprise a twinax cable and / or a triax cable, wherein the outer outer conductor against the inner conductor according to the characteristic impedance is completed. The terminating impedance can implement parts of the load resistance in terms of circuitry.

The stub line may comprise a ferrite bead on the input side, by means of which the supply of the common mode is attenuated or suppressed in the stub line.

It is proposed a builder. Furthermore, a system for

Distance determination comprising a bodybuilder proposed.

Advantageous developments of the invention are specified in the subclaims and described in the description.

Embodiments of the invention will be described with reference to the drawings and the

explained in more detail below description. Show it:

1 shows a circuit according to the prior art,

FIG. 2 shows a first exemplary embodiment,

FIG. 3 shows a second exemplary embodiment,

FIG. 4 shows a third exemplary embodiment,

FIG. 5 shows a further exemplary embodiment,

FIG. 6 shows a fourth exemplary embodiment,

FIG. 7 shows a fifth exemplary embodiment,

FIG. 8 shows a sixth exemplary embodiment,

Figure 9 shows a seventh exemplary embodiment

FIG. 10 shows an eighth exemplary embodiment

FIG. 11 shows a ninth exemplary embodiment FIG. 12 shows a tenth exemplary embodiment and

Figure 13 shows an eleventh exemplary embodiment.

FIG. 2 shows a circuit for a pulse amplifier driver. The circuit comprises a voltage source VO, a first diode D1 and a load output for connecting a load ZL. An anode of the first diode D1 is connected to a first side of the voltage source VO. The load output is connected to a cathode of the first diode D1. The circuit for a pulse amplifier driver includes a second diode D2 and a stub TL. In this case, the stub line TL connects the cathode of the first diode D1 to the anode of the second diode D2. A second load output is connected to a cathode of the second diode D2 and an anode of the second diode D2 to a second side of the second diode D2

Voltage source VO connected.

The stub line TL is designed and / or arranged such that reflections in the common mode of the stub line are attenuated or suppressed with respect to ground.

In the embodiment of Figure 3, the circuit for a pulse amplifier driver further comprises an impedance ZT, which connects the cathode of the first diode D1 with the cathode of the second diode D2. The circuit for a pulse amplifier driver in Figure 3 further includes, as an example of a floating amplifier or switching element, a normally-off transistor T1, wherein the load output is connected to a source terminal of the transistor T1. A drain of the transistor T1 is connected to the second side of the voltage source VO and a gate of the transistor T1 is connected to the cathode of the second diode D2.

First, the T ransistor T 1 is locked. At the circuit input, a current is drawn for the duration of the desired output voltage pulse. This generates a voltage drop - lin - ZO at the input side terminal of the stub line. The first diode D1 conducts and the second diode D2 blocks. The resulting voltage wave passes through the stub line and is reflected in reverse at the short-circuited or low-impedance terminated end. Until the return of the guided wave to the input terminal of the stub line, the input current can be switched off, so that the stub line TL now drives approximately a voltage + lin · ZO on the input terminal. As a result, the second diode D2 is operated in the forward direction and the impedance ZT is formed

corresponding voltage drop, which aufsteuert the transistor T1. In this case, the stub line TL sees the terminating impedance ZT via the second diode D2 and the little backreflection in FIG the stub TL is made in. In this way, the transistor T1 can be driven inverted by the circuit according to the invention in comparison to the simple voltage drop of lin at a load resistor according to the prior art. An operating point adjustment of the switching element takes place when necessary by still adding circuit parts.

According to the invention, a current flow in the drive is required only for the duration of the output pulse, so that in particular with a small duty cycle of the

Output voltage significant power loss can be saved. Since that

If the input signal at the stub line is inverted with short circuit or with low impedance termination, an input current is only required for the duration of the output pulse.

The circuit of the embodiment in Figure 4 further comprises a feedback path FBP with positive feedback, wherein the load output is connected via the feedback path FBP to the cathode of the first diode D1. In this case, the transistor T1, which merely serves as an example of a potential-free amplifier or switching element, is self-blocking.

The feedback path may include, for example, a conductive connection, a resistor, a capacitor, a source follower or a combination of several such circuit parts.

By co-coupling of the circuit output to the circuit node at the cathode of D1 increases with the voltage at the circuit output and the voltage at the circuit node above the impedance ZT, so that the driving stub line is a floating signal source, as long as the transistor T1 as in simple bootstrapping aufsteuert until the output voltage by the height of the

Power supply is limited. When the end of the voltage wave from the stub line TL reaches the transistor gate, the transistor T1 at the control terminal experiences a negative voltage jump and closes, so that now the current through the load ZL again drives the voltage at the circuit output downwards.

In the embodiment of Figure 5, the circuit for a

Pulsverstärkertreibertreiber a capacitor CBT, wherein the load output is connected via the capacitor CBT to the cathode of the first diode D1. Since the feedback path thus transmits only changes of the potential, can be added by adding

Circuit parts a separate operating point setting for the input and output side transistor, eg for self-conducting types done. An optional extension of this exemplary embodiment is a resistor RAP connected in parallel with the capacitor, which is shown in dashed lines in FIG. The feedback path may also include other active components such as another

Sourcefolder included. This is shown in the embodiment of Figure 6. Here arise u. U. several - shown here: two - possible tapping points Voutl and Vout2 for the output voltage. Again, analogous to the preceding example, an AC coupling to the operating point setting is possible.

In an exemplary development of the invention shown in FIG. 7, the circuit signal can be triggered by the current from a bipolar transistor having two cascodes, of which the upper one has the voltage stability necessary for the output voltage. The first and second diodes may be implemented as Schottky diodes to minimize the forward voltage. A drive can be effected for example via a bipolar transistor with bipolar cascode and further cascode consisting of a HEMT transistor.

In an exemplary embodiment, the present invention relates to a short-circuited or similar low-resistance termination of a conductivity type with a clearly defined outer conductor or reference conductor (eg, coaxial, coplanar, grounded, striped, or the like), the outer / Reference potential conductor has floating reference potential, that is not identical to ground, the total capacitance between outer conductor and ground is kept small by compact design and the way of wave propagation inside by wound or folded arrangement is designed such that the longest electrically effective outer dimension of Stub line is small compared to the line length inside the stub line. The potential of the outer conductor may then be varied by bootstrapping, for example, to provide an input-free amplifier or switching element, e.g. to control a transistor in source follower configuration by bootstrapping.

In a further exemplary embodiment, the present invention relates to a shorted or similar low resistance stub whose common mode is not a lumped element, but in which common mode reflections are otherwise reduced, either by Completion of wave propagation in common mode (eg a triax line where the two inner conductors implement the shorted stub and the outer line

approximately completed) or by high-impedance implementation of the

External conductor or the common mode to ground (eg a balanced line with high common-mode impedance or ferrite bead suppressed common-mode impedance Feeding, with the outer conductor to ground floating coax line geometrically far from ground or not necessarily designed as a waveguide high impedance to ground), so that little energy is stored in a common mode wave propagation respectively the reactive impedance. In addition, the financial statements may partially or completely replace the burden of the source follower. A capacitor may be replaced by a conductive connection in the case of a normally-off transistor.

The limitation of the possible output pulse width can, as shown in FIG. 8, be canceled out by multiplexing a plurality of elements in order to drive signals whose

Pulse width is not limited in time, for example, for use in supply modulators for power amplifiers, as a modulator driver or for pulsed measurement.

Figure 1 1 shows a building carrier 1 1f and a laser 1 1 g. The laser is simplified cuboid shown, but may alternatively have the shape of a general prism or general cylinder.

When constructing a laser driver for high currents in short-pulse mode, for example, attention must be paid to low-inductance feeding of the pulsed currents to the laser. This may be achieved by the build-up substrate for a laser whose electrodes extend at different locations along the circumference of the length (eg, bar laser): by (eg, partially) embedding the laser in recesses 11a or 1 1 b or attaching to contact regions 1 1 c, 1 1 d (eg planar side surfaces) of the mounting substrate with a conductive connection, the supply line currents in the layer structure can flow in opposite directions over a wide range, which can reduce the lead inductance. The

Conductor planes of the signals alternately present in the layer structure are then sorted out according to signal type as far as the surface of the building support 1 1 e, 1 1j and after insertion of the laser - if necessary with additional conductive material 12d

Improvement of a terminal - conductively connected to its electrodes.

FIG. 12 shows a building carrier with an inserted laser and one attached to the edge, each connected in a conductive manner.

FIG. 13 shows a laser with associated build-up substrate with longitudinal sectioning of an electrode of the laser. In order to influence the laser dynamics of lasers in pulse mode, it may be necessary to drive individual longitudinal sections of the laser separately. For a laser which is sectioned lengthwise, of the electrodes of which at least one is to be connected separately within a plurality of longitudinal sections 13b, 13c and its electrodes extend in each case at different points of the circumference of the length, this can be realized inductively low with a body builder according to claim 1 1.

In exemplary embodiments of the invention, a feedback loop is implemented via follower stages. For example, as shown in FIG. 9, the circuit for a pulse amplifier driver PVT may be used in a system to drive (optionally via one or more source follower or emitter follower stages SFS, EFS) an output stage AGS and thus a laser LAS to form short optical pulses to create.

For example, as shown in FIG. 10, a LIDAR system, such as a flash LIDAR, which is characterized in that scene illumination with semiconductor laser LAS and optical system OPT is realized, can be driven by the pulse amplifier driver PVT.

Such a system can be used, for example, for distance determination, for example in a vehicle.

Claims

claims

A circuit for driving a floating amplifier or switching element, comprising: a pulsed current source, a first diode (D1), a second diode (D2) and a load output for connecting a load (ZL), an anode of the first diode (D1 ) is connected to a reference potential and a first side of the power source and the first pin of the load output is connected to a cathode of the first diode (D1), a second pin of the load output being connected to a cathode of the second diode (D2) and an anode of the second one Diode (D2) is connected to a second side of the current source, an impedance (ZT) connecting the cathode of the first diode (D1) to the cathode of the second diode (D2), characterized in that the circuit comprises a second diode (D2) and a stub line (TL) connecting the cathode of the first diode (D1) to the anode of the second diode (D2), wherein the stub line (TL) is formed and / or arranged such that common mode reflections in the stub (TL) can be prevented, attenuated or suppressed so that the reference potential for the electromagnetic wave traveling inside the stub (TL) can be varied without the common mode wave propagation of the two stub line signal conductors (TL) together Ground by reflection at the end of the stub (TL) leads to interference.

2. The circuit of claim 1, wherein the controlled amplifier or switching element comprises at least one transistor (T1), wherein the load output with a

Source terminal of the at least one transistor (T1) is connected, wherein a drain of the transistor (T1) to the second side of the voltage source (VO) and a gate of the

Transistor (T 1) is connected to the cathode of the second diode (D2).

3. The circuit of claim 1, further comprising an input side potential-free amplifier or switching element, which has two input terminals and two

Output terminals comprises, wherein the input-side reference potential and the output potential of the circuit according Anspruchl with changes in the output voltage by positive feedback of the output voltage of the amplifier or switching element are carried to the reference potential of the input of the amplifier or switching element.

A circuit according to claim 2 or 3, further comprising a feedback path including a capacitor (CBT) or a conductive connection (RAP) and adapted to provide potential changes at the load output to the circuit node with the cathode of the first one Diode (D1), wherein the transistor is self-blocking when AC coupling to the capacitor (CBT) is not used.

The circuit of claim 2, 3, or 4, further comprising one or more additional source followers inserted in the feedback path.

6. A circuit according to any one of the preceding claims, wherein the stub (TL) is wound, folded and / or configured such that a longest electrically effective outer dimension of the stub (TL) is small compared to the length of the line inside the stub (TL) and the Waveguide on the stub line with short circuit or low impedance compared to the characteristic impedance of the stub line is completed, the impedance of the outer conductor of the stub is realized with respect to ground high impedance.

7. A circuit according to any one of claims 1 to 6, wherein the stub Twinax, Triax or another type of line with third shield conductor comprises, said third shield conductor is completed at the end of the stub corresponding to the characteristic impedance of the common mode of the inner conductor relative to the shield conductor.

8. A circuit according to any one of the preceding claims, wherein the stub line (TL) circuit side comprises a ferrite bead, by means of which the common mode supply is attenuated or suppressed in the stub line.

9. Structural support for a circuit, comprising a laser interface for a laser whose electrodes extend at different points along the circumference of the length, wherein the means of the circuit to be driven laser at least partially in one

Recess on one edge or inside of several flat executed

Conductor layers of the structural support is arranged perpendicular to these conductor layers, wherein the conductor layers are at least partially repeatedly alternately occupied with a signal of an anode and a cathode contact and led out at separate areas of the edge of the building carrier for laser contacting to the edge surface.

10. Structural support for a circuit, with a laser interface for a laser, the electrodes extend at different points along the circumference of the length, wherein the means of the circuit to be driven laser is at least partially disposed on a plurality of surface running conductor layers of the building support perpendicular to this edge-flush , wherein the conductor layers at least partially in several areas alternately with a signal of an anode and a cathode contact are occupied and are led out at separate areas of the edge of the building carrier for laser contacting to the edge surface.

1 1. A building support according to claim 9 or 10, wherein the laser interface for the laser is designed as follows:

The conductor layers are at least within a subregion of a plurality of, for at least one of the laser electrodes separately driven sub-areas repeatedly alternately occupied with the signal of the respective region associated anode and cathode contact and sectioned at separate areas of the edge of the building carrier for laser contacting one of the length to be driven Lasers brought out.

12. A construction carrier according to claim 9, 10 or 11 comprising a laser driver circuit.

13.The building support according to claim 12, wherein the laser driver circuit comprises a circuit according to one of claims 1 to 8.

14. System for determining distance, comprising a laser and a

Pulse amplifier driver with a circuit according to one of claims 1 to 8.

15. A vehicle with a system for determining distance according to claim 14.