TWM553903U - Electronic apparatus with power over coaxial cable function - Google Patents

Abstract

An electronic apparatus with power over coaxial cable function including a transmission port, a low-pass filter, a dynamic impedance circuit and a switching power converter is provided. The transmission port is coupled to a coaxial cable. The low-pass filter is coupled to the transmission port to receive a mixed signal from the coaxial cable and filter the mixed signal to obtain a first power. The dynamic impedance circuit is coupled to the low-pass filter to receive and store the first power and provide a second power accordingly. The switching power converter is coupled to the dynamic impedance circuit to receive the second power and convert the second power to an operation power. The dynamic impedance circuit changes an impedance thereof dynamically in response to a current change of the second power, so as to prevent a noise of the switching power converter from being feedback to the transmission port.

Description

Electronic device with coaxial cable power supply function

The present invention relates to an electronic device, and more particularly to an electronic device having a coaxial cable power supply function.

In a Power over Coax (PoC) system, the main device can provide power through its internal power supply circuit and low-pass circuit, and can provide communication data through its internal transceiver circuit and high-pass circuit. The master device can carry the communication data to the power source and transmit it to the remote device through a coaxial cable. The remote device can low-pass filter the signal of the coaxial cable through its internal low-pass circuit to obtain power, and high-pass filter the signal of the coaxial cable through its internal high-pass circuit to obtain communication data. In this way, the main device can achieve power supply and communication to the remote device through the coaxial cable.

In general, the low-pass circuit of the master device and the low-pass circuit of the remote device usually need to adopt a series combination of a plurality of specific RLC circuits to achieve mutual matching effects, thereby avoiding affecting the impedance characteristics of the data communication band (high frequency band). And preventing the noise of the power supply from being transmitted to the coaxial cable through the low-pass circuit to affect the signal quality of the communication data. Once the signal quality of the communication material is affected, communication between the master device and the remote device will fail. Therefore, the matching between the low-pass circuit of the master device and the low-pass circuit of the remote device is crucial, which is the key to affect the quality of the master device and the remote device product.

However, the use of a particular plurality of RLC circuits in the low pass circuit in the master and remote devices complicates the design of the circuit. In addition, when the remote device is miniaturized, multiple RLC circuits may cause signal interference between the components due to the dense arrangement of the components, resulting in high difficulty in circuit design. In particular, if the remote device uses a switching power conversion circuit to process the power supply, the noise generated by the switching of the switching power conversion circuit may still be fed back to the coaxial cable through the RLC circuits, thereby Interfere with communication data.

In view of this, the novel creation provides an electronic device having a coaxial cable power supply function, thereby solving the problems described in the prior art.

The electronic device created by the novel comprises a transmission port, a low-pass filter circuit, a dynamic impedance circuit and a switching power conversion circuit. The transmission port is used to couple the coaxial cable for power and data transmission operations. The low pass filter circuit is coupled to the transmission port to receive the mixed signal from the coaxial cable, and filters the mixed signal to obtain the first power source. The dynamic impedance circuit is coupled to the low pass filter circuit to receive and store the first power source and thereby provide a second power source. The switching power conversion circuit is coupled to the dynamic impedance circuit to receive the second power source, and converts the voltage of the second power source to generate a working power source required for the operation of the electronic device. The dynamic impedance circuit dynamically changes the impedance of the dynamic impedance circuit in response to a change in the amount of current of the second power source to prevent noise of the switched power conversion circuit from being fed back to the transmission port.

In an embodiment of the present invention, when the current of the second power source is greater than or equal to the reference current value in response to the switching operation of the switching power conversion circuit, the dynamic impedance circuit adjusts the impedance to extract the first power source. The current is maintained at the reference current value to prevent the noise generated by the switching power conversion circuit from switching back to the transmission port.

In an embodiment of the novel creation, the dynamic impedance circuit includes a current limiter and a capacitor. The current limiter is coupled between the low pass filter circuit and the switched power conversion circuit for transmitting the first power source and limiting the current drawn from the first power source. The capacitor is coupled between the current limiter and the ground for storing energy according to the first power source and cooperating with the current limiter to provide the second power source.

In an embodiment of the present invention, when the current of the second power source is less than the reference current value, the current limiter uses the first power source as the second power source to charge the capacitor and supply power to the switched power conversion circuit.

In an embodiment of the present invention, when the current of the second power source is greater than or equal to the reference current value, the current limiter and the capacitor provide a second power source to supply power to the switched power conversion circuit, and the current limiter limits the first power source. The current is at the reference current value.

In an embodiment of the novel creation, the low pass filter circuit is an inductor.

In an embodiment of the novel creation, the dynamic impedance circuit includes a bipolar junction transistor and a capacitor. The emitter end of the bipolar junction transistor is coupled to the low pass filter circuit. The set terminal of the bipolar junction transistor is coupled to the switched power conversion circuit. The base terminal of the bipolar junction transistor receives the reference voltage to bring the bipolar junction transistor into a conducting state. The capacitor is coupled between the collector terminal of the bipolar junction transistor and the ground terminal for storing energy according to the first power source and cooperating with the dual carrier junction transistor to provide the second power source.

In an embodiment of the novel creation, the dynamic impedance circuit includes a field effect transistor and a capacitor. The source terminal of the field effect transistor is coupled to the low pass filter circuit. The 汲 terminal of the field effect transistor is coupled to the switching power conversion circuit. The gate terminal of the field effect transistor receives the reference voltage to bring the field effect transistor into a conducting state. The capacitor is coupled between the 汲 terminal of the field effect transistor and the ground for storing energy according to the first power source and cooperating with the field effect transistor to provide the second power source.

In an embodiment of the novel creation, the dynamic impedance circuit includes a low dropout regulator and a capacitor. The low dropout regulator is coupled between the low pass filter circuit and the switched power conversion circuit for transmitting the first power source and limiting the current drawn from the first power source. A capacitor is coupled between the low dropout regulator and the ground for storing energy according to the first power source and cooperating with the low dropout regulator to provide the second power source.

Based on the above, in the electronic device proposed by the novel creation embodiment, the dynamic impedance circuit can prevent the noise generated by the switching power conversion circuit from being fed back to the coaxial cable to avoid interference with the communication data on the coaxial cable. Therefore, the low pass filter circuit in the electronic device does not need to use a series combination of a plurality of RLC circuits to match the low pass filter circuit of the master device at the other end of the coaxial cable. In this way, not only the difficulty and complexity of the circuit design of the electronic device can be reduced, but also the miniaturization of the electronic device is facilitated.

The above described features and advantages of the present invention will become more apparent and understood from the following description.

In order to make the content of the novel creation easier to understand, the following specific examples are examples in which the novel creation can be implemented. In addition, wherever possible, the same reference numerals in the FIGS.

Please refer to FIG. 1 . FIG. 1 is a block diagram showing an application and a circuit block of an electronic device 100 having a coaxial cable power supply function according to an embodiment of the present invention. As shown in FIG. 1 , the main device 900 is coupled to one end of the coaxial cable 500 , and the electronic device 100 is coupled to the other end of the coaxial cable 500 . The main device 900 can supply power to the electronic device 100 through the coaxial cable 500. In addition to this, the main device 900 and the electronic device 100 can communicate (signal transmission) through the coaxial cable 500. In detail, the main device 900 can mix the data signal to be transmitted with the power source to generate and output the mixed signal MS to the coaxial cable 500.

As shown in FIG. 1, the electronic device 100 may include a transmission port 110, a low-pass filter circuit 120, a dynamic impedance circuit 130, a switching power conversion circuit 140, a high-pass filter circuit 150, and a transceiver circuit 160, but the novel creation is not limited thereto. The transmission port 110 can be, for example, a coaxial cable connector for coupling the coaxial cable 500 for power and data transmission operations with the main device 900. The low pass filter circuit 120 is coupled to the transfer port 110 to receive the mixed signal MS from the coaxial cable 500, and filters the mixed signal MS to obtain the first power source PW1.

The dynamic impedance circuit 130 is coupled to the low pass filter circuit 120 to receive and store the first power source PW1, and accordingly provides the second power source PW2. The switching power conversion circuit 140 is coupled to the dynamic impedance circuit 130 to receive the second power PW2, and converts the voltage of the second power PW2 to generate the operating power PWS required for the operation of the electronic device 100.

The high pass filter circuit 150 is coupled to the transfer port 110 to receive the mixed signal MS from the coaxial cable 500, and high pass filters the mixed signal MS to obtain the data signal DS. The transceiver circuit 160 is coupled to the high-pass filter circuit 150 to receive the data signal DS, and transmits the data signal DS to a back-end circuit (not shown) of the electronic device 100 for subsequent signal processing.

In particular, the dynamic impedance circuit 130 can dynamically change the impedance of the dynamic impedance circuit 130 in response to a change in the amount of current of the second power source PW2 to prevent the noise feedback of the switched power conversion circuit 140 from being fed back to the transmission port 110 and the coaxial cable. 500. As a result, it is possible to prevent the data signal DS in the mixed signal MS from being disturbed and causing the communication failure between the main device 900 and the electronic device 100 to occur.

Further, when the current I2 drawn by the switching power conversion circuit 140 from the second power source PW2 is smaller than the reference current value Ir, the impedance inside the dynamic impedance circuit 130 is in a low impedance state, so the dynamic impedance circuit 130 will be the first The power source PW1 functions as the second power source PW2 to supply power to the switching power source conversion circuit 140. At this time, the current I1 of the first power source PW1 is smaller than the reference current value Ir.

When the switching power conversion circuit 140 performs the switching operation and the current I2 drawn from the second power source PW2 is greater than or equal to the reference current value Ir, the dynamic impedance circuit 130 can adjust the internal impedance to be extracted from the first power source PW1. The current I1 is maintained at the reference current value Ir to prevent the noise generated by the switching power conversion circuit 140 from being switched back to the transmission port 110 and the coaxial cable 500. In other words, in the case where the switch in the switching power conversion circuit 140 is switched and the current I2 drawn from the second power source PW2 changes greatly, the current I1 of the first power source PW1 does not exceed the reference current value Ir. In this way, a large change in the current I1 of the first power source PW1 can be avoided to generate a surge noise on the transmission port 110.

In an embodiment of the present invention, the low pass filter circuit 120 can be, for example, an inductor, but the novel creation is not limited thereto.

In an embodiment of the present invention, the switched power conversion circuit 140 can be, for example, a boost power conversion circuit or a buck power conversion circuit. The architecture and operation modes of the above various power conversion circuits are all familiar to those skilled in the art of creation and related fields, and thus will not be further described herein.

In an embodiment of the present invention, the high-pass filter circuit 150 can be implemented by a common high-pass filter, and the transceiver circuit 160 can be implemented by using a known transmit-receive circuit, but the novel creation is not limited thereto.

Referring to FIG. 1 and FIG. 2 together, FIG. 2 is a circuit block diagram of a dynamic impedance circuit 130 according to an embodiment of the present invention. The dynamic impedance circuit 130 can include a current limiter 232 and a capacitor 234, but this novel creation is not the case. The current limiter 232 is coupled between the low pass filter circuit 120 (shown in FIG. 1 ) and the switched power conversion circuit 140 (shown in FIG. 1 ) for transmitting the first power source PW1 and limiting the extraction from the first power source. Current I1 of PW1. The capacitor 234 is coupled between the current limiter 232 and the ground GND for storing energy according to the first power source PW1 and cooperating with the current limiter 232 to provide the second power source PW2.

The operation of extracting power from the electronic device 100 will be described in more detail below. Referring to FIG. 1 , FIG. 3A and FIG. 3B , FIG. 3A and FIG. 3B are schematic diagrams showing an equivalent circuit when the electronic device 100 draws power according to an embodiment of the present invention. Since the power supplied from the main device 900 (shown in FIG. 1) is a direct current or a low frequency alternating current and cannot pass through the high pass filter circuit 150, the high pass filter circuit 150 can be regarded as an open state from the viewpoint of power. In contrast, the power can pass through the low-pass filter circuit 120 as the first power source PW1, so that the low-pass filter circuit 120 can be regarded as the on state from the viewpoint of power. In addition, the current limiter 232 can be equivalent to a controllable current source, and the maximum value of the current I1 provided is the reference current value Ir.

As shown in FIG. 3A, when the current I2 of the second power source PW2 is less than the reference current value Ir, the current limiter 232 can use the first power source PW1 as the second power source PW2 to simultaneously charge the capacitor 234 (transmitting current I3) and The switching power conversion circuit 140 is powered (transmission current I2).

In contrast, as shown in FIG. 3B, when the current I2 of the second power source PW2 is greater than or equal to the reference current value Ir, the current limiter 232 limits the current I1 of the first power source PW1 to the reference current value Ir, and the current limiter 232 The capacitor 234 will provide a second power source PW2 to power the switched mode power conversion circuit 140. That is, the current limiter 232 and the capacitor 234 respectively supply the switching power supply conversion circuit 140 in parallel through the currents I1 and I3'. It can be understood that since the current limiter 232 limits the current I1 drawn from the first power source PW1, the current limiting characteristic of the current limiter 232 can be substantially regarded as increasing the impedance of the dynamic impedance circuit 130.

Referring to FIG. 1 and FIG. 4 together, FIG. 4 is a circuit block diagram of a dynamic impedance circuit 430 according to another embodiment of the present invention. The dynamic impedance circuit 430 may include a Low Dropout Regulator (LDO) 432 and a capacitor 434, but the present invention does not. The low-dropout regulator is coupled between the low-pass filter circuit 120 (shown in FIG. 1) and the switched-mode power conversion circuit 140 (shown in FIG. 1) for transmitting the first power source PW1, and limiting the extraction from the first Current I1 of power supply PW1. The capacitor 434 is coupled between the low dropout regulator 432 and the ground GND for storing energy according to the first power source PW1 and cooperating with the low dropout regulator 432 to provide the second power source PW2. The low dropout regulator 432 can be implemented using a known regulated integrated circuit with a current limiting function. Since the low-dropout regulator 432 has a function of voltage regulation and current limiting, it is possible to prevent noise generated by the switching power conversion circuit 140 from being fed back to the coaxial cable 500.

Referring to FIG. 1 and FIG. 5 together, FIG. 5 is a circuit block diagram of a dynamic impedance circuit 530 according to another embodiment of the present invention. The dynamic impedance circuit 530 may include a Bipolar Junction Transistor (BJT) 532 and a capacitor 534, but the present invention does not. The emitter terminal of the bipolar junction transistor 532 is coupled to the low pass filter circuit 120. The collector terminal of the bipolar junction transistor 532 is coupled to the switched power conversion circuit 140, and the base terminal of the bipolar junction transistor 532. The reference voltage Vref is received to bring the bipolar junction transistor 532 into a conducting state. The capacitor 534 is coupled between the collector terminal of the bipolar junction transistor 532 and the ground GND for storing energy according to the first power source PW1 and cooperating with the bipolar junction transistor 532 to provide a second Power supply PW2. It can be understood that since the bipolar junction transistor 532 itself has dynamic impedance and current limiting characteristics, the noise generated when the switching power conversion circuit 140 is switched can be prevented from being fed back to the coaxial cable 500. It should be noted that although the bipolar junction transistor 532 shown in the embodiment of FIG. 5 is a pnp type bipolar junction transistor, the novel creation is not limited thereto, and other embodiments of the novel creation are described. The bipolar junction transistor 532 of FIG. 5 can also be implemented by using an npn-type bipolar junction transistor.

Referring to FIG. 1 and FIG. 6 together, FIG. 6 is a circuit block diagram of a dynamic impedance circuit 630 according to another embodiment of the present invention. The dynamic impedance circuit 630 may include a Field-Effect Transistor (FET) 632 and a capacitor 634, but the present invention is not. The source terminal of the field effect transistor 632 is coupled to the low pass filter circuit 120. The drain terminal of the field effect transistor 632 is coupled to the switched power conversion circuit 140. The gate terminal of the field effect transistor 632 receives the reference voltage Vref to enable field effect. The crystal 632 is in an on state. The capacitor 634 is coupled between the 汲 terminal of the field effect transistor 632 and the ground GND for storing energy according to the first power source PW1 and cooperating with the field effect transistor 632 to provide the second power source PW2. It can be understood that since the field effect transistor 632 itself has the characteristics of dynamic impedance and current limiting (such as the characteristics of the saturation region), the noise feedback generated when the switching power conversion circuit 140 is switched can be prevented from being fed back to the coaxial cable 500. . Incidentally, although the field effect transistor 632 illustrated in the embodiment of FIG. 6 is a P-type Metal-Oxide-Semiconductor Field-Effect Transistor (abbreviation: PMOS), The novel creation is not limited thereto, and in other embodiments of the novel creation, the field effect transistor 632 of FIG. 6 can also be implemented using various types of field effect transistors.

In summary, in the electronic device proposed by the novel creation embodiment, the dynamic impedance circuit can prevent the noise generated by the switching power conversion circuit from being fed back to the coaxial cable to avoid interference with the communication data on the coaxial cable. . Therefore, the low pass filter circuit in the electronic device does not need to use a series combination of a plurality of RLC circuits to match the low pass filter circuit of the master device at the other end of the coaxial cable. In this way, not only the difficulty and complexity of the circuit design of the electronic device can be reduced, but also the miniaturization of the electronic device is facilitated.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the novel creation, and any person skilled in the art can make some changes without departing from the spirit and scope of the novel creation. Retouching, the scope of protection of this new creation is subject to the definition of the scope of the patent application attached.

100‧‧‧Electronic devices
110‧‧‧Transportation
120‧‧‧Low-pass filter circuit
130, 430, 530, 630‧‧‧ dynamic impedance circuit
140‧‧‧Switching power conversion circuit
150‧‧‧High-pass filter circuit
160‧‧‧Transceiver circuit
232‧‧‧ current limiter
234, 434, 534, 634 ‧ ‧ capacitors
432‧‧‧Low Dropout Regulator
500‧‧‧ coaxial cable
532‧‧‧Double carrier junction transistor
632‧‧‧ field effect transistor
900‧‧‧Main device
DS‧‧‧Information signal
GND‧‧‧ ground terminal
MS‧‧ mixed signal
I1, I2, I3, I3'‧‧‧ current
Ir‧‧‧ reference current value
PW1‧‧‧ first power supply
PW2‧‧‧second power supply
PWS‧‧‧Working power supply
Vref‧‧‧reference voltage

The following drawings are part of the specification of the present invention, and illustrate exemplary embodiments of the present invention, which together with the description of the specification illustrate the principles of the novel creation. 1 is a block diagram showing an application and a circuit block of an electronic device having a coaxial cable power supply function according to an embodiment of the present invention. 2 is a circuit block diagram of a dynamic impedance circuit according to an embodiment of the present invention. 3A and FIG. 3B are schematic diagrams showing an equivalent circuit when an electronic device draws power according to an embodiment of the present invention. 4 is a circuit block diagram of a dynamic impedance circuit according to another embodiment of the present invention. FIG. 5 is a circuit block diagram of a dynamic impedance circuit according to another embodiment of the present invention. FIG. 6 is a circuit block diagram of a dynamic impedance circuit according to another embodiment of the present invention.

100‧‧‧Electronic devices

110‧‧‧Transportation

120‧‧‧Low-pass filter circuit

130‧‧‧Dynamic impedance circuit

140‧‧‧Switching power conversion circuit

150‧‧‧High-pass filter circuit

160‧‧‧Transceiver circuit

500‧‧‧ coaxial cable

900‧‧‧Main device

DS‧‧‧Information signal

MS‧‧ mixed signal

I1, I2‧‧‧ current

Ir‧‧‧ reference current value

PW1‧‧‧ first power supply

PW2‧‧‧second power supply

PWS‧‧‧Working power supply

Claims (9)

An electronic device with a coaxial cable power supply function, comprising: a transmission port for coupling a coaxial cable for power supply and data transmission operation; a low pass filter circuit coupled to the transmission port for receiving from the coaxial cable a mixed signal of the line, and filtering the mixed signal to obtain a first power source; a dynamic impedance circuit coupled to the low pass filter circuit to receive and store the first power source, and accordingly provide a second power source; And a switching power conversion circuit coupled to the dynamic impedance circuit to receive the second power source, and converting the voltage of the second power source to generate a working power required for operation of the electronic device, wherein the dynamic impedance circuit is responsive to The amount of current of the second power source changes to dynamically change an impedance of the dynamic impedance circuit to prevent a noise of the switched power conversion circuit from being fed back to the transmission port. The electronic device of claim 1, wherein the dynamic impedance circuit increases the impedance when the current of the second power source is greater than or equal to a reference current value in response to the switching operation of the switching power conversion circuit. The current drawn from the first power source is maintained at the reference current value to prevent the noise generated by the switching power conversion circuit from being switched back to the transmission port. The electronic device of claim 1, wherein the dynamic impedance circuit comprises: a current limiter coupled between the low pass filter circuit and the switched power conversion circuit for transmitting the first power source And limiting the current drawn from the first power source; and a capacitor coupled between the current limiter and a ground for storing energy according to the first power source and cooperating with the current limiter To provide the second power source. The electronic device of claim 3, wherein: when the current of the second power source is less than a reference current value, the current limiter uses the first power source as the second power source to charge the capacitor And supplying power to the switched power conversion circuit. The electronic device of claim 3, wherein: when the current of the second power source is greater than or equal to a reference current value, the current limiter and the capacitor provide the second power source to convert the switched power source The circuit is powered, and the current limiter limits the current of the first power source to the reference current value. The electronic device of claim 1, wherein the low pass filter circuit is an inductor. The electronic device of claim 1, wherein the dynamic impedance circuit comprises: a dual carrier junction transistor, the emitter end of the bipolar junction transistor is coupled to the low pass filter circuit, the pair The collector terminal of the carrier junction transistor is coupled to the switching power conversion circuit, the base terminal of the bipolar junction transistor receives a reference voltage to make the bipolar junction transistor conductive; and a capacitor And being coupled between the collector terminal of the bipolar junction transistor and a ground terminal for storing energy according to the first power source and cooperating with the dual carrier junction transistor to provide the first Two power supplies. The electronic device of claim 1, wherein the dynamic impedance circuit comprises: a field effect transistor, the source terminal of the field effect transistor is coupled to the low pass filter circuit, and the field effect transistor has a 汲 extreme coupling Connected to the switching power conversion circuit, the gate terminal of the field effect transistor receives a reference voltage to make the field effect transistor conductive; and a capacitor coupled to the drain terminal of the field effect transistor and a ground Between the ends, for storing energy according to the first power source, and working in cooperation with the field effect transistor to provide the second power source. The electronic device of claim 1, wherein the dynamic impedance circuit comprises: a low dropout voltage regulator coupled between the low pass filter circuit and the switched power conversion circuit for transmitting the a power source and limiting current drawn from the first power source; and a capacitor coupled between the low voltage drop regulator and a ground for storing energy according to the first power source, and the low voltage The down regulators operate in concert to provide the second power source.