Standby isolated power supply circuit

Abstract

The utility model discloses a standby isolated power supply circuit, it is a kind of switch power supply's power factor correction transformer's isolated power supply circuit, including alternating current power input and bridge rectifier module, power factor correction module are connected in proper order, using power factor correction module is electrically connected with isolated power module, standby isolated power supply module respectively, using secondary isolated power control module is connected with isolated power module, standby isolated power supply module signal respectively, the utility model increases a group of isolated type coil as the power source of standby auxiliary voltage source with power factor correction transformer, can realize when the main isolated transformer output stops, power factor correction transformer still can provide a group of isolated power supply product's control baseplate power use, can stably provide a group of isolated power to product control baseplate use, and realize the winding of multiplex power factor correction transformer, without additional standby transformer, simplify power supply structure, reduce cost.

Description

Technical Field

[0001] This utility model relates to the field of switching power supply technology, specifically to a standby isolation power supply circuit for a power factor correction transformer. Background Technology

[0002] With the increasing popularity of switching power supplies and the continuous development and launch of various smart products, it is necessary to design two power supplies or adopt a light-load mode to ensure the normal operation of the intelligent control board while limiting the standby current of high-power power supplies. However, in either case, the main isolation transformer is in working mode, which greatly reduces the lifespan of the switching power supply and makes it easy for the standby current to exceed the specifications.

[0003] Furthermore, if the power factor correction module of a power supply only performs the single function of improving the power factor and stabilizing the input and output voltage, without reusing its transformer windings, it leads to redundancy in the power supply structure and increased costs. Therefore, there is an urgent need for a power supply that can reuse the function of the power factor correction transformer and realize the switching between main power supply and standby isolated power supply. Utility Model Content

[0004] This invention proposes a standby isolation power supply circuit for a power factor correction transformer to improve the power factor of the power supply, increase power utilization, reduce harmonic current, and enable a wider input voltage range and more stable output voltage of the switching power supply, thereby solving the practical problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A standby isolated power supply circuit is characterized by comprising an AC power input, a bridge rectifier module, a power factor correction module, an isolated power supply module, a standby isolated power supply module, and a secondary isolated power supply control module. The AC power input is sequentially connected to the bridge rectifier module and the power factor correction module. The power factor correction module is electrically connected to the isolated power supply module and the standby isolated power supply module, respectively. The secondary isolated power supply control module is signal connected to the isolated power supply module and the standby isolated power supply module, respectively.

[0007] The AC power input consists of endpoint (21) and endpoint (22) and is used to connect to an external AC power source.

[0008] Bridge rectifier module: includes a bridge rectifier (23) that rectifies the AC power input into a pulsating DC power.

[0009] Power factor correction module: includes power factor correction transformer (24), first group of pulse modulation module (25), first power transistor (26), isolation diode (27), filter capacitor (28) and primary ground terminal (81); wherein, the power factor correction transformer (24) is provided with two groups of secondary coils, and the power factor pulse modulation drive module power supply (31) and primary ground (81) of one group of secondary coils are electrically connected to the first group of pulse modulation module (25) to provide it with working power; the DC power after bridge rectification is boosted to above 300V by the power factor correction transformer (24) and the first power transistor (26), and then rectified by the isolation diode (27) and stored in the filter capacitor (28).

[0010] The isolated power supply module includes a main isolation transformer (63), a second group of pulse modulation modules (61), a second power transistor (62), a rectifier diode, a filter capacitor (65), and output terminals (66 (OUT+) and 67 (OUT-). The filter capacitor (28) is electrically connected to the primary end of the main isolation transformer (63). The second group of pulse modulation modules (61) is connected to the power transistor (62). The second group of pulse modulation modules (61) drives the second power transistor (62) to generate a high-frequency voltage at the primary end of the main isolation transformer (63). The secondary end generates a secondary voltage through electromagnetic coupling induction. After rectification by the rectifier diode and filtering by the filter capacitor (65), the main power is output from the output terminal.

[0011] The standby isolated power supply module includes a standby power supply (33) and a secondary ground terminal (82), which is composed of another set of secondary coils of the power factor correction transformer (24), a rectifier and filter submodule and the secondary ground terminal (82). The set of secondary coils obtains electrical energy through electromagnetic coupling, and after being processed by the rectifier and filter submodule, it outputs an isolated standby voltage to power the equipment control board.

[0012] The secondary isolation power supply control module is electrically connected to the second group of pulse modulation modules (61) and the standby isolation power supply module, and is used to detect the load status of the equipment. When the equipment is in standby mode, the secondary isolation power supply control module outputs a signal to shut down the second group of pulse modulation modules (61) and stop the main isolation transformer (63) from outputting. At the same time, it triggers the standby isolation power supply module to start, and the secondary coil of the power factor correction transformer (24) continuously provides isolation power.

[0013] The present invention has the following beneficial effects:

[0014] This invention implements a standby isolated power supply circuit based on a power factor correction transformer (PFCD). By adding an isolation coil to the PFCD as an auxiliary voltage source, the circuit allows the PFCD to continue providing isolated power to the product's control board even when the main isolation transformer's output stops. Furthermore, even when the main isolation transformer has completely stopped outputting, the circuit can still stably provide isolated power to the product's control board within the standby current specification limits of the switching power supply. It also reuses the windings of the PFCD, eliminating the need for an additional standby transformer, simplifying the power supply structure, reducing costs, and ensuring the safety of the control board's power supply by completely isolating the secondary grounding terminal from the primary grounding terminal.

[0015] The overall circuit improves the power factor of the power supply, increases power utilization, reduces harmonic current, and enables the switching power supply to have a wider input voltage range and a more stable output voltage. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the circuit structure of this utility model;

[0017] 21 AC power input terminal, 21 AC power input terminal II, 23 Bridge rectifier, 24 Power factor correction transformer, 25 First group pulse modulation module, 26 Power transistor, 27 Isolation diode, 28 Filter capacitor, 31 Power factor pulse modulation drive module power supply, 81 Primary ground terminal, 33 Standby power supply, 82 Secondary isolation ground, 61 Second group pulse modulation drive module, 62 Power transistor, 63 Main isolation transformer, 64 Rectifier diode, 65 Filter capacitor, 66 Output terminal +, 67 Output terminal -. Detailed Implementation

[0018] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0019] Reference Figure 1A standby isolated power supply circuit is an isolated power supply circuit for a power factor correction transformer in a switching power supply. It includes an AC power input, a bridge rectifier module, a power factor correction module, an isolated power supply module, a standby isolated power supply module, and a secondary isolated power supply control module. The AC power input is sequentially connected to the bridge rectifier module and the power factor correction module. The power factor correction module is electrically connected to both the isolated power supply module and the standby isolated power supply module. The secondary isolated power supply control module is signal-connected to both the isolated power supply module and the standby isolated power supply module.

[0020] The AC power input consists of AC power input terminal 21 and AC power input terminal 22, used to connect to an external AC power source. The bridge rectifier module includes a bridge rectifier 23, which rectifies the AC power input into pulsating DC power. The power factor correction module includes a power factor correction transformer 24, a first group of pulse modulation modules 25, a power transistor 26, an isolation diode 27, a filter capacitor 28, and a primary ground terminal 81. The power factor correction transformer 24 has two sets of secondary coils. The power factor pulse modulation drive module power supply 31 and the primary ground terminal 81 of one set of secondary coils are electrically connected to the first group of pulse modulation modules 25 to provide them with operating power. The DC power after bridge rectification is boosted to above 300V by the power factor correction transformer 24 and the power transistor 26, and then rectified by the isolation diode 27 before being stored in the filter capacitor 28.

[0021] The isolated power supply module includes a main isolation transformer 63, a second pulse modulation module 61, a power transistor 62, a rectifier diode, a filter capacitor 65, and output terminals 66 and 67. The filter capacitor 28 is electrically connected to the primary end of the main isolation transformer 63. The second pulse modulation module 61 drives the power transistor 62 to generate a high-frequency voltage at the primary end of the main isolation transformer 63. The secondary end generates a secondary voltage through electromagnetic coupling induction. After rectification by the rectifier diode and filtering by the filter capacitor 65, the main power is output from the output terminals.

[0022] The standby isolated power supply module includes a standby power supply 33 and a secondary ground terminal 82, which consists of another set of secondary coils of the power factor correction transformer 24, a rectifier and filter submodule, and the secondary ground terminal 82. The set of secondary coils obtains electrical energy through electromagnetic coupling, and after being processed by the rectifier and filter submodule, it outputs an isolated standby voltage to power the equipment control board.

[0023] The secondary isolation power supply control module is electrically connected to the second group of pulse modulation modules 61 and the standby isolation power supply module, and is used to detect the load status of the equipment. When the equipment is in standby mode, the secondary isolation power supply control module outputs a signal to shut down the second group of pulse modulation modules 61, causing the main isolation transformer 63 to stop outputting; at the same time, it triggers the standby isolation power supply module to start, and the secondary coil of the power factor correction transformer 24 continuously provides isolation power.

[0024] Example 2

[0025] The circuit structure of Example 1 is adopted and implemented for industrial PLC. The parameter adjustment and workflow are as follows: Main power supply parameters: DC 24V / 5A (supplying PLC actuators, relays, etc.);

[0026] Power supply parameters: DC 5V / 0.4A (supplying the PLC central secondary isolated power control module and communication module);

[0027] Design adjustments: The turns ratio of the secondary coil 2 of the power factor correction transformer 24 is adjusted from 1:0.2 in Example 1 to 1:0.25 to adapt to DC 5V / 0.4A output; the primary-secondary turns ratio of the main isolation transformer 63 is adjusted to 1:0.15 to meet DC24V output.

[0028] Working circuit flow: Same as in Example 1. When the PLC is working normally, the isolation power supply module runs. When in standby mode, the main isolation transformer stops, and the standby isolation power supply module continuously supplies power to the secondary isolation power control module, ensuring that the PLC communication and status monitoring functions are not interrupted.

[0029] The above implementation fully realizes an isolated power supply circuit based on a power factor correction transformer. By adding an isolated coil to the power factor correction transformer as an auxiliary voltage source, it is possible to ensure that when the output of the main isolation transformer stops, the power factor correction transformer can still provide a set of isolated power to power the product's control board. Furthermore, even when the main isolation transformer has completely stopped outputting, it can still stably provide a set of isolated power to the product's control board within the standby current specification limits of the switching power supply. It also enables the reuse of the windings of the power factor correction transformer, eliminating the need for an additional standby transformer, simplifying the power supply structure, reducing costs, and ensuring the safety of the control board's power supply by using a secondary ground terminal that is completely isolated from the primary ground terminal.

[0030] The overall circuit improves the power factor of the power supply, increases power utilization, reduces harmonic current, and enables the switching power supply to have a wider input voltage range and a more stable output voltage.

[0031] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0032] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A standby isolated power supply circuit, characterized in that, It includes an AC power input, a bridge rectifier module, a power factor correction module, an isolated power supply module, a standby isolated power supply module, and a secondary isolated power supply control module. The AC power input is connected in sequence to the bridge rectifier module and the power factor correction module. The power factor correction module is electrically connected to the isolated power supply module and the standby isolated power supply module, respectively. The secondary isolated power supply control module is signal connected to the isolated power supply module and the standby isolated power supply module, respectively.

2. The isolated power supply circuit according to claim 1, characterized in that, The standby isolated power supply module includes a standby power supply (33) and a secondary ground terminal (82), which is composed of another set of secondary coils of the power factor correction transformer (24), a rectifier filter submodule and the secondary ground terminal (82).

3. The standby isolated power supply circuit according to claim 2, characterized in that, The bridge rectifier module includes a bridge rectifier (23) that rectifies the AC power input into pulsating DC power.

4. The standby isolated power supply circuit according to claim 3, characterized in that, The power factor correction module includes a power factor correction transformer (24), a first group of pulse modulation modules (25), a first power transistor (26), an isolation diode (27), a filter capacitor (28), and a primary ground terminal (81). The power factor correction transformer (24) is equipped with two sets of secondary coils. The power factor pulse modulation drive module power supply (31) and the primary ground terminal (81) of one set of secondary coils are electrically connected to the first group of pulse modulation modules (25) to provide power. The DC power after bridge rectification is boosted to above 300V by the power factor correction transformer (24) and the first power transistor (26), and then rectified by the isolation diode (27) and stored in the filter capacitor (28).

5. The standby isolated power supply circuit according to claim 4, characterized in that, The isolated power supply module includes a main isolation transformer (63), a second group of pulse modulation modules (61), a second power transistor (62), a rectifier diode (64), a filter capacitor (65), and output terminals + (66) and - (67); the filter capacitor (28) is electrically connected to the primary terminal of the main isolation transformer (63), and the second group of pulse modulation modules (61) is connected to the second power transistor (62).

6. The standby isolated power supply circuit according to claim 5, characterized in that, The secondary isolation power supply control module is electrically connected to the second group of pulse modulation modules (61) and the standby isolation power supply module.

7. The standby isolated power supply circuit according to claim 5, characterized in that, The AC power input consists of terminal (21) and terminal (22), and is connected to an external AC power source.

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