TW201421856A - DC to DC conversion system - Google Patents

Abstract

A DC to DC conversion system comprises a voltage regulator, for generating a regulated voltage according to an input voltage, a voltage detector, for generating an enable signal and a switch signal according to the regulated voltage, a battery voltage of a battery and a system voltage of an external system, a DC to DC conversion module, coupled between the voltage regulator and the battery, for enabling converting the regulated voltage to a converted voltage, to charge the battery with the converted voltage, and a switch module, coupled between the external system and the voltage regulator and the battery, for switching to connect the external system with the voltage regulator and the battery.

Description

DC to DC conversion system

The present invention relates to a DC to DC conversion system, and more particularly to a DC to DC conversion system that avoids excessive surge current to an external system and prevents backflow of a battery voltage.

Generally speaking, due to the low voltage of a small power battery such as a notebook computer, when the input voltage is present (such as from an AC to DC adapter, AC/DC adapter), the input voltage is directly switched to supply power to the system. And charge the battery at the same time.

For example, please refer to FIG. 1 , which is a schematic diagram of a power supply control circuit 10 of one of the prior art. As shown in FIG. 1, the power supply control circuit 10 includes Schottky diodes 102, 104. Under this architecture, since the voltage of the battery 12 is always less than an input voltage VI, the input voltage VI supplies power to the system 14 and simultaneously charges the battery 12 when the input voltage VI is present, and when the input voltage VI does not exist, Battery 12 is on system 14.

However, for a power battery, since the voltage of the power battery is about 20 to 33 V and may be larger than the input voltage, and it is used for a system such as a working machine or a large motor load, a large current is required, so if a conventional one is used, Power supply control circuit 10 is constructed on a power battery In a DC to DC conversion system, the power battery may be backwashed to the input voltage, and the large current generates excessive heat loss on the Schottky diode. In view of this, the prior art has been improved.

Accordingly, it is a primary object of the present invention to provide a DC-to-DC conversion system that avoids excessively high inrush current to an external system and prevents back-up of a battery voltage.

The invention discloses a DC-to-DC conversion system, which comprises a power supply voltage stabilization circuit for generating an adjustment voltage according to an input voltage, and a voltage detector for using the voltage adjustment voltage, a battery voltage of a battery and a battery The system voltage of the external system generates an activation signal and a switching signal; the DC-to-DC conversion module is coupled between the power voltage stabilization circuit and the battery, and is configured to start and convert the adjustment voltage according to the startup signal. Generating a conversion voltage and charging the battery with the conversion voltage; and a switching module coupled between the external system and the power voltage stabilization circuit and the battery, for switching the external connection according to the switching signal The system is coupled to the power regulator circuit and the battery.

As shown in FIG. 2, FIG. 2 is a schematic diagram of a DC to DC conversion system 20 according to an embodiment of the present invention. As shown in FIG. 2, the DC-DC conversion system 20 includes a power voltage regulator circuit 202, a voltage detector 204, a DC-to-DC converter module 206, and a switching module 208. Simply put, power supply voltage The circuit 202 can generate a regulated voltage VR according to an input voltage VIN from one of an AC/DC adapter. The voltage detector 204 can be based on the regulated voltage VR, a battery voltage VBAT of one of the batteries 22, and an external connection. The system voltage VS of the system 24 generates an activation signal ENA and a switching signal SWT. The DC-to-DC conversion module 206 is coupled between the power voltage stabilization circuit 202 and the battery 22, and can start the conversion regulation voltage according to the startup signal ENA. The VR generates a conversion voltage VC and charges the battery 22 with the conversion voltage VC. The switching module 208 is coupled between the external system 24 and the power voltage stabilization circuit 202 and the battery 22 for switching the external system according to the switching signal SWT. 24 is connected to the power voltage regulator circuit 202 and the battery 22. The battery 22 is preferably a power battery. In this way, the voltage detector 204 can appropriately control the DC-DC conversion module 206 and the switching module 208 according to the adjustment voltage VR, the battery voltage VBAT, and the system voltage VS to supply power to the external system 24 and charge the battery 22, Further, the battery voltage VBAT of the battery 22 is prevented from being backflushed to the regulated voltage VR via the DC-to-DC converter module 206 or the system 24.

For details, please refer to FIG. 3, which is a schematic diagram of the voltage detector 204 for controlling the reference voltages VA, VB, VC, VD, VE in FIG. 2, wherein the reference voltage VA>VB> VC>VD>VE, and the reference voltage VA is preferably sufficient to supply one of the external system 24 and the battery 22, and the reference voltage VB is preferably sufficient to supply a voltage to the external system 24. In this case, when the voltage detector 204 detects that the regulation voltage VR rises above the reference voltage VB sufficient to supply the external system 24, the startup signal ENA may indicate that the DC-to-DC conversion module 206 does not start to turn off the power supply voltage regulation. The circuit 202 is coupled to the battery 22, and the switching signal SWT can indicate the switching module 208. The connection between the external connection system 24 and the power supply voltage stabilization circuit 202 is connected and the connection between the external system 202 and the battery 22 is cut off to supply power to the external system 24 by the regulation voltage VR; and the regulation voltage VR rises above the external system 24 and When the reference voltage VA of the battery 22 is VA (that is, greater than the battery voltage VBAT), the start signal ENA indicates that the DC-to-DC conversion module 206 is activated to connect the power supply voltage stabilization circuit 202 and the battery 22, and the switching signal SWT still indicates the switching. The module 208 is connected between the external system 24 and the power voltage stabilizing circuit 202 and cuts off the connection between the external system 202 and the battery 22 to supply power to the external system 24 and charge the battery 22 by the regulating voltage VR. In this way, the voltage detector 204 can appropriately control the DC-DC conversion module 206 and the switching module 208 to prevent the adjustment voltage VR (about 28V) from being lower than the battery voltage VBAT (about 20V~33V) of the battery 22. The battery voltage VBAT of the battery 22 is backflushed to the regulated voltage VR via the DC-to-DC converter module 206 or system 24.

Then, after the adjustment voltage VR starts to supply power to the external system 24 and the battery 22 is charged, if the adjustment voltage VR falls below the reference voltage VC, the startup signal ENA indicates that the DC-to-DC conversion module 206 does not start to turn off the power supply. The voltage circuit S202 is connected to the battery 22, and the switching signal SWT still indicates that the switching module 208 is connected between the external system 24 and the power voltage stabilizing circuit 202 and cuts off the connection between the external system 202 and the battery 22 to adjust the voltage. The VR external system 24 is powered and stops charging the battery 22; if the adjustment voltage VR then drops below the reference voltage VD, the enable signal ENA still indicates that the DC-to-DC conversion module 206 is not activated to turn off the power regulator circuit 202 and The batteries 22 are connected to each other, and the switching signal SWT indicates that the switching module 208 cuts off the connection between the external system 24 and the power voltage stabilizing circuit 202 and turns on the external system 202. Connected to the battery 22 to switch the battery 22 to the external system 24; finally, if the battery 22 starts to supply power to the external system 24, and the battery voltage VBAT drops below the reference voltage VE, the start signal ENA still indicates DC The DC conversion module 206 is not activated to close the connection between the power supply voltage stabilization circuit 202 and the battery 22, and the switching signal SWT indicates that the switching module 208 cuts off the connection between the external system 24 and the power supply voltage stabilization circuit 202 and cuts off the external connection. The system 202 is coupled to the battery 22 to completely stop the external system 24 when both the regulation voltage VR and the battery voltage VBAT are too low. In this way, the voltage detector 204 can appropriately control the DC-DC conversion module 206 and the switching module 208 to supply power to the external system 24 and charge the battery 22 according to the changes of the regulation voltage VR and the battery voltage VBAT.

On the other hand, since the external system 24 can require a large current for a system such as a working machine or a large motor load, when the regulating voltage VR or the battery 22 is supplied to the external system 24, the respective voltage levels may be for power supply. The level drops and the level rises when the power supply is stopped. In this case, please continue to refer to FIG. 2, the voltage detector 204 can include a delay unit 210 and a latch 212 (latch). The delay unit 210 can delay the adjustment voltage VR and the battery voltage VBAT by a specific time T1 to determine whether the adjustment voltage VR and the battery voltage VBAT remain substantially unchanged within a certain time T1, and determine the adjustment voltage VR and the battery voltage VBAT to reach the above reference. Whether the voltages of VA, VB, VC, VD, and VE are only transient changes. The latch 212 can lock the adjustment voltage VR and the battery voltage VBAT for a specific time T2 when the voltage VR and the battery voltage VBAT are substantially maintained within a certain time T1 to ensure that the reference voltages VA, VB, VC, VD are reached. When the control is switched to the VE level, there will be no subsequent transient changes. When the conduction or the closing operation is performed, a large current instantaneously causes an excessive pressure difference and is switched. In this way, the voltage detector 204 can perform appropriate operations when adjusting the voltage VR and the battery voltage VBAT transiently.

Furthermore, as shown in FIG. 2, the switching module 208 can include switches SW1, SW2 and soft start units 214, 216. The switch SW1 is coupled between the external system 24 and the power supply voltage stabilization circuit 202, and can switch between the external system 24 and the power supply voltage stabilization circuit 202 according to the switching signal SWT. The switch SW2 is coupled between the external system 24 and the battery 22. The connection between the external system 24 and the battery 22 can be switched according to the switching signal SWT. The soft start unit 214 and the switch SW1 are coupled in parallel between the external system 24 and the power voltage stabilization circuit 202, and can slowly increase the system voltage VS according to the switching signal SWT when the adjustment voltage VR is greater than the system voltage VS to a certain extent. The starter 216 is coupled in parallel with the switch SW2 between the external system 24 and the battery 22. According to the switching signal SWT, the system voltage VS is slowly increased when the adjustment voltage VR is greater than the system voltage VS. In other words, in order to avoid a sudden connection between the external system 24 and the adjustment voltage VR or the battery 22, the excessive voltage difference causes an excessive surge current, and the voltage detector 204 detects the voltage of the system VS and the voltage of the regulation voltage VR or the battery voltage VBAT. When the difference is small, the switch SW1 or SW2 is directly turned on or off to switch, and when the voltage difference between the detection system voltage VS and the regulated voltage VR or the battery voltage VBAT is greater than a certain degree, the switch SW1 or SW2 is slowly boosted. System voltage VS to avoid excessive surge current. In this way, the switching module 208 can effectively protect the external system 24 to avoid excessive impact current.

It should be noted that the main spirit of the present invention is that the DC-DC conversion module 206 and the switching module 208 can be appropriately controlled according to the adjustment voltage VR, the battery voltage VBAT, and the system voltage VS to supply power to the external system 24 and to the battery 22 Charging, which is generally known to those skilled in the art, may be modified or varied, without being limited thereto. For example, the implementation of the voltage detector 204 and the switching module 208 is not limited to the circuit shown in FIG. 2, but may be other methods as long as the individual functions can be achieved; in addition, the switches SW1 and SW2 can be The relay is implemented, but may be a transistor or other switching device, and is not limited thereto.

In the prior art, the power supply control circuit 10 is constructed in a DC-to-DC conversion system of a power battery, which may cause the power battery to backflow the input voltage, and the large current generates excessive heat loss on the Schottky diode. In contrast, the voltage detector 204 of the present invention can prevent the battery voltage VBAT of the battery 22 from being back-regulated by the DC-to-DC conversion module 206 or the system 24, and can further adjust the voltage VR and the battery voltage VBAT. When the state changes, perform appropriate operations. In addition, the switching module 208 can effectively protect the external system 24 to avoid excessive surge current.

The above are only the preferred embodiments of the present invention, and all changes and modifications made to the scope of the present invention should be within the scope of the present invention.

10‧‧‧Power control circuit

12, 22‧‧‧ battery

14‧‧‧System

102, 104‧‧‧ diode

20‧‧‧DC to DC conversion system

24‧‧‧External system

202‧‧‧Power voltage regulator circuit

204‧‧‧Voltage Detector

206‧‧‧DC to DC converter module

208‧‧‧Switching module

210‧‧‧Delay unit

212‧‧‧Latch

214, 216‧‧‧ soft start unit

VI, VIN‧‧‧ input voltage

VR‧‧‧Adjust voltage

VBAT‧‧‧ battery voltage

VS‧‧‧ system voltage

ENA‧‧‧ start signal

SWT‧‧‧Switch signal

VC‧‧‧Switching voltage

VA, VB, VC, VD, VE‧‧‧ reference voltage

SW1, SW2‧‧‧ switch

Figure 1 is a schematic diagram of a power supply control circuit of one of the prior art.

2 is a schematic diagram of a DC-to-DC conversion system according to an embodiment of the present invention.

Figure 3 is a schematic diagram of a voltage detector used to control the reference voltage in Figure 2.

20‧‧‧DC to DC conversion system

202‧‧‧Power voltage regulator circuit

204‧‧‧Voltage Detector

206‧‧‧DC to DC converter module

208‧‧‧Switching module

210‧‧‧Delay unit

212‧‧‧Latch

214, 216‧‧‧ soft start unit

VIN‧‧‧ input voltage

VR‧‧‧Adjust voltage

VBAT‧‧‧ battery voltage

VS‧‧‧ system voltage

ENA‧‧‧ start signal

SWT‧‧‧Switch signal

VC‧‧‧Switching voltage

SW1, SW2‧‧‧ switch

Claims (11)

A DC to DC conversion system includes: a power supply voltage stabilization circuit for generating an adjustment voltage according to an input voltage; and a voltage detector for adjusting the voltage according to the battery a battery voltage and a system voltage of an external system, generating a start signal and a switching signal; a DC-to-DC conversion module coupled between the power voltage stabilization circuit and the battery for using the startup signal, The switching voltage is activated to generate a conversion voltage, and the battery is charged by the conversion voltage; and a switching module is coupled between the external system and the power voltage stabilizing circuit and the battery for switching according to the switching The signal is switched between the external system and the power voltage stabilizing circuit and the battery. The DC-to-DC conversion system of claim 1, wherein the startup signal indicates that the DC-to-DC conversion module does not start when the adjustment voltage rises above a first reference voltage, and the switching signal indicates the switching module The connection between the external system and the power voltage stabilizing circuit is turned on and the connection between the external system and the battery is cut off. The DC-to-DC conversion system of claim 2, wherein the startup signal indicates that the DC-to-DC conversion module is activated when the adjustment voltage rises above a second reference voltage, and the switching signal indicates the switching module The connection between the external system and the power voltage stabilizing circuit is turned on and the connection between the external system and the battery is cut off, and the second reference voltage is higher than the first reference voltage. The DC-to-DC conversion system of claim 3, wherein the startup signal indicates that the DC-to-DC conversion module does not start when the adjustment voltage drops below a third reference voltage, and the switching signal indicates the switching The module turns on the connection between the external system and the power voltage stabilizing circuit and cuts off the connection between the external system and the battery, and the third reference voltage is lower than the first reference voltage. The DC-DC conversion system of claim 4, wherein the startup signal indicates that the DC-to-DC conversion module does not start when the adjustment voltage drops below a fourth reference voltage, and the switching signal indicates the switching The module cuts off the connection between the external system and the power voltage stabilizing circuit and turns on the connection between the external system and the battery, and the fourth reference voltage is lower than the third reference voltage. The DC-DC conversion system of claim 5, wherein the startup signal indicates that the DC-to-DC conversion module does not start when the battery voltage drops below a fifth reference voltage, and the switching signal indicates the switching The module cuts off the connection between the external system and the power voltage stabilizing circuit and cuts off the connection between the external system and the battery, and the fifth reference voltage is lower than the fourth reference voltage. The DC-DC conversion system of claim 1, wherein the voltage detector comprises a delay unit for delaying the adjustment voltage and the battery voltage by a first specific time to determine the first specific time. Adjust the voltage and the battery voltage to remain approximately the same. The DC-to-DC conversion system of claim 7, wherein the voltage detector includes a latch for maintaining the regulated voltage and the battery voltage substantially constant during the first specific time. The adjustment voltage and the battery voltage are locked for a second specific time. The DC-to-DC conversion system of claim 1, wherein the switching module includes: a first switch coupled between the external system and the power voltage stabilizing circuit, configured to switch according to the switching signal The external system is coupled to the power voltage stabilizing circuit; and a second switch is coupled between the external system and the battery for switching the connection between the external system and the battery according to the switching signal. The DC-to-DC conversion system of claim 9, wherein the switching module further comprises: a first soft start unit coupled to the external switch and the power supply voltage regulator in parallel with the first switch Between the circuits, according to the switching signal, when the adjustment voltage is greater than a certain degree of the system voltage, the system voltage is slowly increased; and a second soft start unit is coupled to the external system in parallel with the second switch Between the battery and the battery, the system voltage is slowly increased according to the switching signal when the battery voltage is greater than the system voltage. The DC-to-DC conversion system of claim 1, wherein the battery is a power battery.