CN110635664A

CN110635664A - Communication system and voltage converter

Info

Publication number: CN110635664A
Application number: CN201810641891.7A
Authority: CN
Inventors: 黄振家; 蔡聪行
Original assignee: Wistron Neweb Corp
Current assignee: Wistron Neweb Corp
Priority date: 2018-06-21
Filing date: 2018-06-21
Publication date: 2019-12-31

Abstract

A communication system includes a set-top box, a low noise block down converter, and a voltage converter. The voltage converter is coupled between the set-top box and the low noise down converter. The voltage converter includes a DC switch, a voltage regulator, and a controller. The DC switcher is coupled between an input node and an output node. The voltage regulator is coupled between the input node and the output node. The controller is used for detecting an input potential at the input node. If the input voltage is higher than or equal to a threshold voltage, the controller will turn off the DC switch. If the input voltage is lower than the threshold voltage, the controller will turn on the DC switch.

Description

Communication system and voltage converter

Technical Field

The present invention relates to a Communication System, and more particularly, to a Communication System and a Voltage Converter (Voltage Converter) with a very low Voltage Drop (Voltage Drop)

Background

Conventional Voltage stabilizing elements include Linear regulators (Linear regulators), Low dropout regulators (LDOs), DC-to-DC switching converters (DC-to-DC switching converters), and the like. When the conventional voltage regulator device has a low input potential, the potential difference (or voltage drop) between the output potential and the input potential is still usually larger than 0.1V, which is not favorable for the operation performance and output quality of the voltage regulator device. In view of the above, a new solution is needed to overcome the problems of the prior art.

Disclosure of Invention

In a preferred embodiment, the present invention provides a communication system, comprising: a set-top box; a low noise block down converter; and a voltage converter, the set-top box is coupled between the low noise downconverters through the voltage converter, wherein the voltage converter comprises: a DC switcher coupled between an input node and an output node; a voltage regulator coupled between the input node and the output node; and a controller for detecting an input potential at the input node, wherein if the input potential is higher than or equal to a threshold potential, the controller will turn off the dc switch, and if the input potential is lower than the threshold potential, the controller will turn on the dc switch.

In some embodiments, the input node of the voltage converter is configured to receive the input potential from the set-top box, and the output node of the voltage converter is configured to output an output potential to the low noise downconverter.

In some embodiments, the voltage regulator converts the input voltage to the output voltage having a constant level if the dc switch is turned off.

In some embodiments, if the dc switch is turned on, the output voltage is substantially equal to the input voltage.

In some embodiments, the dc switch includes: a first transistor having a control terminal, a first terminal, and a second terminal, wherein the control terminal of the first transistor is coupled to a first node, the first terminal of the first transistor is coupled to the input node, and the second terminal of the first transistor is coupled to the output node.

In some embodiments, the first Transistor is a P-channel Metal-Oxide-Semiconductor Field-Effect Transistor (PMOS Transistor).

In some embodiments, the controller comprises: a first resistor having a first end and a second end, wherein the first end of the first resistor is coupled to the input node and the second end of the first resistor is coupled to a second node; a second resistor having a first end and a second end, wherein the first end of the second resistor is coupled to the second node and the second end of the second resistor is coupled to a third node; and a Zener diode having an anode and a cathode, wherein the anode of the Zener diode is coupled to a ground potential and the cathode of the Zener diode is coupled to the third node.

In some embodiments, the controller further comprises: a second transistor having a control terminal, a first terminal, and a second terminal, wherein the control terminal of the second transistor is coupled to the second node, the first terminal of the second transistor is coupled to the input node, and the second terminal of the second transistor is coupled to the first node; and a third resistor having a first end and a second end, wherein the first end of the third resistor is coupled to the first node and the second end of the third resistor is coupled to the ground potential.

In some embodiments, the second Transistor is a PNP-type Bipolar Junction Transistor (PNP-type BJT).

In some embodiments, the voltage converter further comprises: a first capacitor having a first terminal and a second terminal, wherein the first terminal of the first capacitor is coupled to the input node and the second terminal of the first capacitor is coupled to a ground potential; and a second capacitor having a first terminal and a second terminal, wherein the first terminal of the second capacitor is coupled to the output node and the second terminal of the second capacitor is coupled to the ground potential.

In another preferred embodiment, the present invention provides a voltage converter coupled between a set-top box and a low noise block down converter, and comprising: a DC switcher coupled between an input node and an output node; a voltage regulator coupled between the input node and the output node; and a controller for detecting an input potential at the input node, wherein if the input potential is higher than or equal to a threshold potential, the controller will turn off the dc switch, and if the input potential is lower than the threshold potential, the controller will turn on the dc switch.

Drawings

Fig. 1 is a diagram illustrating a communication system according to an embodiment of the invention.

Fig. 2 is a schematic diagram illustrating a voltage converter according to an embodiment of the invention.

Fig. 3 is a diagram illustrating an operation characteristic of the voltage converter according to an embodiment of the invention.

Fig. 4 is a schematic diagram illustrating a voltage converter according to another embodiment of the invention.

Detailed Description

In order to make the objects, features and advantages of the present invention comprehensible, fig. 1 illustrates an embodiment of the present invention and is described in detail below with reference to the accompanying drawings.

Certain terms are used throughout the description and claims to refer to particular components. As one skilled in the art will appreciate, hardware manufacturers may refer to a component by different names. The present specification and claims do not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to. The term "substantially" means within an acceptable error range, within which a person skilled in the art can solve the technical problem to achieve the basic technical result. In addition, the term "coupled" is used herein to encompass any direct or indirect electrical connection. Thus, if a first device couples to a second device, that connection may be through a direct electrical connection, or through an indirect electrical connection via other devices and connections.

Fig. 1 is a schematic diagram illustrating a Communication System (Communication System)100 according to an embodiment of the invention. As shown in fig. 1, the communication system 100 includes: a Set-Top Box (STB) 110, a Low Noise Block Down Converter (LNB) 120, and a Voltage Converter (Voltage Converter) 130. The voltage converter 130 is coupled between the set-top box 110 and the low noise downconverter 120. The voltage converter 130 has an input node NIN for receiving an input voltage VIN from the set-top box 110 and an output node NOUT for outputting an output voltage VOUT to the low noise block converter 120. Generally, the set-top box 110 can be regarded as a Power Supply Device (Power Supply Device), the input voltage VIN can be converted into the output voltage VOUT by the voltage converter 130, and the low noise block down converter 120 can be powered by the output voltage VOUT.

The Voltage converter 130 includes a direct current (dc) Switch Element 140, a Voltage Regulator (Voltage Regulator)150, and a Controller 160. The dc switch 140 is coupled between the input node NIN and the output node NOUT, and is operable in an on State (Closed State) or an off State (Open State). The voltage regulator 150 is also coupled between the input node NIN and the output node NOUT, and is configured to selectively stabilize a voltage level of the output voltage VOUT. The controller 160 may include a Voltage Detector (not shown), such as: one volt meter (Voltmeter). The controller 160 is configured to detect the input potential VIN at the input node NIN, and control the operating state of the dc switch 140 according to the input potential VIN. If the input Voltage VIN is higher than or equal to a Threshold Voltage VTH, the controller 160 will Open (Open) the dc switch 140; on the contrary, if the input voltage VIN is lower than the threshold voltage VTH, the controller 160 will turn on (Close) the dc switch 140.

The operating principle of the voltage converter 130 may be as follows. If the dc switch 140 is turned off, the voltage regulator 150 can convert the input voltage VIN into an output voltage VOUT having a constant level; conversely, if the dc switch 140 is turned on, the output voltage VOUT may be substantially equal to the input voltage VIN. Since the on-resistance of the dc switch 140 is small, the potential difference between the output potential VOUT and the input potential VIN is almost negligible. In general, the dc switch 140 is used to provide a Bypass Path (Bypass Path) between the output node NOUT and the input node NIN. When the input voltage VIN is too low, the dc switch 140 can directly couple the output node NOUT and the input node NIN. This design helps to eliminate the undesirable Voltage Drop (Voltage Drop) generated by the Voltage regulator 150, thereby improving the operability and Reliability (Reliability) of the Voltage converter 130.

In some embodiments, the low noise downconverter 120 is further coupled to a Dish Antenna (Dish Antenna) to receive a Satellite Signal (Satellite Signal). The dish antenna can receive electromagnetic waves with various polarization directions according to the output potential VOUT with different potential levels, so that the set-top box 110 can select different channels (channels) related to satellite signals by changing the input potential VIN. In some embodiments, the voltage converter 130 and the low noise downconverter 120 are both disposed in an Outdoor Unit (ODU), wherein the set top box 110 is coupled to the Outdoor Unit via a Cable (Cable). Since the voltage drop of the voltage converter 130 is very low, the situation of insufficient supply voltage due to the loss of the outdoor unit caused by too long cable lines can be reduced. In other embodiments, the voltage converter 130 may be used as a separate component, and not necessarily collocated with the set-top box 110 and the low-noise downconverter 120.

The following embodiment will describe a detailed circuit configuration of the voltage converter 130. It should be noted that the drawings and description are only exemplary and are not intended to limit the invention.

Fig. 2 is a schematic diagram illustrating a voltage converter 230 according to an embodiment of the invention. The voltage converter 230 has an input node NIN for receiving an input voltage VIN and an output node NOUT for outputting an output voltage VOUT. In the embodiment of fig. 2, the voltage converter 230 includes a dc switch 240, a regulator 250, and a controller 260, wherein the regulator 250 is coupled between the input node NIN and the output node NOUT.

The dc switch 240 includes a first Transistor (Transistor) M1. The first transistor M1 has a control terminal, a first terminal, and a second terminal, wherein the control terminal of the first transistor M1 is coupled to a first node N1, the first terminal of the first transistor M1 is coupled to the input node NIN, and the second terminal of the first transistor M1 is coupled to the output node NOUT. For example, the first Transistor M1 may be a P-channel Metal-Oxide-Semiconductor Field-Effect Transistor (PMOS Transistor). In detail, the pmos has a Gate (Gate), a Source (Source), and a Drain (Drain), wherein the Gate of the pmos is coupled to a first node N1, the Source of the pmos is coupled to the input node NIN, and the Drain of the pmos is coupled to the output node NOUT.

The controller 260 includes a first Resistor (Resistor) R1, a second Resistor R2, a third Resistor R3, a Zener Diode (Zener Diode) DZ1, and a second transistor Q1. The first resistor R1 has a first end and a second end, wherein the first end of the first resistor R1 is coupled to the input node NIN, and the second end of the first resistor R1 is coupled to a second node N2. The second resistor R2 has a first terminal and a second terminal, wherein the first terminal of the second resistor R2 is coupled to the second node N2, and the second terminal of the second resistor R2 is coupled to a third node N3. The zener diode DZ1 has an Anode (Anode) and a Cathode (Cathode), wherein the Anode of the zener diode DZ1 is coupled to a ground potential VSS, and the Cathode of the zener diode DZ1 is coupled to the third node N3. The second transistor Q1 has a control terminal, a first terminal, and a second terminal, wherein the control terminal of the second transistor Q1 is coupled to the second node N2, the first terminal of the second transistor Q1 is coupled to the input node NIN, and the second terminal of the second transistor Q1 is coupled to the first node N1. For example, the second Transistor Q1 may be a PNP-type Bipolar Junction Transistor (PNP-type BJT). In detail, the PNP bipolar junction transistor has a Base (Base), an Emitter (Emitter), and a Collector (Collector), wherein the Base of the PNP bipolar junction transistor is coupled to the second node N2, the Emitter of the PNP bipolar junction transistor is coupled to the input node NIN, and the Collector of the PNP bipolar junction transistor is coupled to the first node N1. The third resistor R3 has a first end and a second end, wherein the first end of the third resistor R3 is coupled to the first node N1, and the second end of the third resistor R3 is coupled to the ground potential VSS.

Fig. 3 is a diagram illustrating the operation characteristics of the voltage converter 230 according to an embodiment of the invention, wherein the horizontal axis represents the input voltage VIN and the vertical axis represents the output voltage VOUT. According to the measurement result of FIG. 3, when the input potential VIN is lower than a threshold potential VTH (e.g., about 15V), the output potential VOUT will be substantially equal to the input potential VIN; when the input potential VIN is higher than or equal to the threshold potential VTH, the output potential VOUT will be substantially constant (e.g., about 12V). Therefore, the design of the voltage converter 230 can effectively eliminate the undesired voltage drop of the output voltage VOUT, especially for the relatively low input voltage VIN.

Please refer to fig. 2 and 3 together. The operating principle of the voltage converter 230 may be as follows. If the input voltage VIN is lower than the threshold voltage VTH, the Zener diode DZ1 will not operate in the Breakdown Region (Breakdown Region), and the voltage at the second node N2 will be substantially equal to the input voltage VIN. At this time, the second transistor Q1 is turned off, so that the potential of the first node N1 is substantially equal to the ground potential VSS. Thus, the first transistor M1 is enabled (enabled) to directly couple the output node NOUT and the input node NIN, and the voltage regulator 250 is disabled due to a bypass path between the output node NOUT and the input node NIN.

On the contrary, if the input voltage VIN is equal to or higher than the threshold voltage VTH, the Zener diode DZ1 will operate in the breakdown region to pull down the voltage at the second node N2. At this time, the second transistor Q1 is turned on and pulls the potential of the first node N1 high. Accordingly, the first transistor M1 will be disabled (Disable) and the aforementioned bypass path will disappear, so that the voltage regulator 250 can generate the output voltage VOUT with a constant level according to the input voltage VIN.

It should be noted that the threshold Voltage VTH is determined according to a Breakdown Voltage (Breakdown Voltage) of the zener diode DZ1 and a resistance ratio (R1/R2) of the first resistor R1 and the second resistor R2. For example, if the ratio of the resistances of the first resistor R1 and the second resistor R2 decreases, the threshold potential VTH will increase; on the contrary, if the ratio of the resistances of the first resistor R1 and the second resistor R2 increases, the threshold voltage VTH will decrease. The circuit designer can adjust the threshold voltage VTH by changing the ratio of the resistances of the first resistor R1 and the second resistor R2 to meet different requirements.

Fig. 4 is a schematic diagram illustrating a voltage converter 430 according to another embodiment of the invention. Fig. 4 is similar to fig. 2. In the embodiment of fig. 4, the voltage converter 430 further includes a first Capacitor (Capacitor) C1 and a second Capacitor C2. The first capacitor C1 has a first terminal and a second terminal, wherein the first terminal of the first capacitor C1 is coupled to the input node NIN, and the second terminal of the first capacitor C1 is coupled to the ground potential VSS. The second capacitor C2 has a first terminal and a second terminal, wherein the first terminal of the second capacitor C2 is coupled to the output node NOUT, and the second terminal of the second capacitor C2 is coupled to the ground potential VSS. The addition of the first capacitor C1 and the second capacitor C2 helps to filter the high frequency noise of the voltage converter 430, so as to further improve the output quality of the voltage converter 430. The remaining features of the voltage converter 430 of fig. 4 are similar to those of the voltage converter 230 of fig. 2, so that the embodiments can achieve similar operation effects.

The present invention provides a novel voltage converter which can effectively eliminate the non-ideal voltage drop of the voltage stabilizing element and improve the overall operation performance and reliability. Therefore, the present invention is suitable for various communication systems.

It should be noted that the above-mentioned potential, current, resistance, inductance, capacitance, and other device parameters are not limitations of the present invention. The designer can adjust these settings according to different needs. The communication system and the voltage converter of the present invention are not limited to the states illustrated in fig. 1-4. The present invention may include only any one or more features of any one or more of the embodiments of fig. 1-4. In other words, not all illustrated features may be required to implement the communication system and the voltage converter of the present invention. Although the embodiment of the present invention uses a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) as an example, the present invention is not limited thereto, and other kinds of transistors can be used by those skilled in the art, for example: bipolar Junction Transistors (BJTs), Junction Gate Field Effect transistors (JFETs), or Fin Field Effect transistors (finfets), among others.

Ordinal numbers such as "first," "second," "third," etc., in the specification and claims are not to be given a sequential order, but are merely used to identify two different elements having the same name.

Although the present invention has been described with reference to particular embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

[ description of symbols ]

100-a communication system;

110-set-top box;

120-low noise frequency demultiplier;

130. 230, 430-voltage converter;

140. 240-dc switcher;

150. 250-voltage stabilizer;

160. 260-a controller;

c1-first capacitor;

c2-second capacitor;

DZ1 Zener diode;

m1-first transistor;

n1-first node;

n2-second node;

n3-third node;

NIN-input node;

NOUT-output node;

q1-second transistor;

r1-first resistor;

r2-second resistor;

r3 third resistor;

VIN-input potential;

VOUT-output potential;

VSS to ground potential;

VTH-critical potential.

Claims

1. A communication system, comprising:

a set-top box;

a low noise block down converter; and

a voltage converter, the set-top box coupled between the low noise downconverters through the voltage converter, wherein the voltage converter comprises:

a DC switcher coupled between an input node and an output node;

a voltage regulator coupled between the input node and the output node; and

a controller for detecting an input potential at the input node, wherein if the input potential is higher than or equal to a threshold potential, the controller will turn off the dc switch, and if the input potential is lower than the threshold potential, the controller will turn on the dc switch.

2. The communication system of claim 1, wherein the input node of the voltage converter is configured to receive the input voltage from the set-top box and the output node of the voltage converter is configured to output an output voltage to the low noise downconverter.

3. The communication system of claim 2, wherein the voltage regulator converts the input voltage to the output voltage having a constant level if the dc switch is turned off.

4. The communication system of claim 2, wherein the output voltage is substantially equal to the input voltage if the DC switch is turned on.

5. The communication system of claim 2, wherein the dc switch comprises:

a first transistor having a control terminal, a first terminal, and a second terminal, wherein the control terminal of the first transistor is coupled to a first node, the first terminal of the first transistor is coupled to the input node, and the second terminal of the first transistor is coupled to the output node.

6. The communication system of claim 5 wherein the first Transistor is a P-channel Metal-Oxide-Semiconductor Field-Effect Transistor (PMOSTransistor).

7. The communication system of claim 5, wherein the controller comprises:

a first resistor having a first end and a second end, wherein the first end of the first resistor is coupled to the input node and the second end of the first resistor is coupled to a second node;

a second resistor having a first end and a second end, wherein the first end of the second resistor is coupled to the second node and the second end of the second resistor is coupled to a third node; and

a Zener diode having an anode and a cathode, wherein the anode of the Zener diode is coupled to a ground potential and the cathode of the Zener diode is coupled to the third node.

8. The communication system of claim 7, wherein the controller further comprises:

a second transistor having a control terminal, a first terminal, and a second terminal, wherein the control terminal of the second transistor is coupled to the second node, the first terminal of the second transistor is coupled to the input node, and the second terminal of the second transistor is coupled to the first node; and

a third resistor having a first end and a second end, wherein the first end of the third resistor is coupled to the first node and the second end of the third resistor is coupled to the ground potential.

9. The communication system of claim 8 wherein the second Transistor is a PNP-type Bipolar Junction Transistor (PNP-type BJT).

10. The communication system of claim 1, wherein the voltage converter further comprises:

a first capacitor having a first terminal and a second terminal, wherein the first terminal of the first capacitor is coupled to the input node and the second terminal of the first capacitor is coupled to a ground potential; and

a second capacitor having a first terminal and a second terminal, wherein the first terminal of the second capacitor is coupled to the output node and the second terminal of the second capacitor is coupled to the ground potential.

11. A voltage converter coupled between a set-top box and a low noise block down converter, comprising:

a DC switcher coupled between an input node and an output node;

a voltage regulator coupled between the input node and the output node; and

12. The voltage converter of claim 11, wherein the input node of the voltage converter is configured to receive the input potential from the set-top box and the output node of the voltage converter is configured to output an output potential to the low noise downconverter.

13. The voltage converter as claimed in claim 12, wherein if the dc switch is turned off, the voltage regulator converts the input potential to the output potential having a constant level.

14. The voltage converter of claim 12, wherein the output voltage is substantially equal to the input voltage if the dc switch is turned on.

15. The voltage converter of claim 12, wherein the dc switch comprises:

16. The voltage converter as claimed in claim 15, wherein the first Transistor is a P-channel Metal-Oxide-Semiconductor Field-Effect Transistor (pmos Transistor).

17. The voltage converter of claim 15, wherein the controller comprises:

18. The voltage converter of claim 17, wherein the controller further comprises:

19. The voltage converter as claimed in claim 18, wherein the second Transistor is a PNP-type Bipolar Junction Transistor (PNP-type BJT).

20. The voltage converter of claim 1, further comprising: