KR20130073321A - High efficiency high voltage poewer supply - Google Patents

Abstract

PURPOSE: A high-voltage power circuit is provided to supply power to an IC usinig variable current by directly connecting an high-voltage AC terminal and the IC, thereby minimizing heat generation in a chip and thus improving efficiency. CONSTITUTION: A circuit (100) comprises a diode (D), a constant current source (110) in an IC chip, a Vac voltage detecting circuit (120), a Vcc voltage detecting circuit (130) and an Icc variable control circuit (140). If external voltage is applied to a pin of the IC chip, the Vac voltage detecting circuit senses the amount of the voltage. Depending on the amount of the voltage, the Icc variable control circuit controls the constant current source to adjust the amount of current, in order to minimize power consumption. [Reference numerals] (120) Vac voltage detecting circuit; (130) Vcc voltage detecting circuit; (140) Icc variable control circuit

Description

High Efficiency High Voltage Poewer Supply

The present invention relates to a high-voltage power supply circuit, and has the same form of generating power by connecting directly to an IC at an AC high voltage stage, thereby controlling a variable current rather than a constant current to prevent unnecessary power consumption and to minimize heat generation in a chip. It relates to a high voltage power supply circuit.

Systems separated into primary and secondary sides using transformers typically use auxiliary windings for powering the integrated circuit (IC) from the primary side. The use of auxiliary windings has the advantage of obtaining a stable supply voltage, but has the problem of complicated transformer design. In addition, IC power design can be a challenge for applications such as AC LED systems that connect LEDs directly to the AC line. To drive the AC LED system, a separate auxiliary winding for VCC power supply must be designed or current can be supplied from the AC line using a high voltage device.

If there is no problem with VCC power supply, LED can be driven with only one inductor without auxiliary winding, but when the auxiliary winding is needed for VCC, a normal transformer design is required, causing a problem of space and cost increase.

6A and 6B, when the auxiliary winding is not conventionally used to drive the LED, the VCC stage is formed by a constant current source generated in the IC by connecting the high voltage pin (HV) of the IC to an AC high voltage line of several hundred volts or more. It mainly uses the method of supplying current and charging the capacitor of the VCC power supply, and operates the IC circuit to control the corresponding circuit of the LED system controlled by VCC. In order to supply the Icc current required inside the IC chip, a constant constant current flows regardless of the voltage level applied to the HV pin as shown in FIGS. 6A and 6B. The IC operation may appear to be stable because the constant current required inside the IC flows in almost all sections except for a few low voltage sections. As a result, unnecessary power consumption occurs. And when a constant current flows in all sections where AC voltage is applied, a considerable amount of heat generation occurs in the chip. For example, if a power supply with a constant current of 1mA is supplied from an AC 220V line, an average of 0.2W of power loss occurs and all of this heat is generated inside the chip. Therefore, the surface temperature of the chip rises to maintain a high temperature. This will adversely affect the operating characteristics and life of the. In particular, in the peak portion of the sinusoidal input as shown in Figure 7 may be more vulnerable because the high power state corresponding to about 1.4 times the input RMS value is maintained for a considerable time. This unnecessary power consumption is generated by the heat inside the chip and adversely affects IC operation or reliability. Since this is a fundamental problem related to the generation and supply of constant current, even if the Icc level is lowered to some extent through the improvement of the internal circuit, the expected effect is not generated.

In addition, a Zener diode or shunt regulator can be connected to the VCC stage to prevent abnormal power supply rise and maintain a stable VCC voltage when the applied Icc value is higher than the actual required level in the chip. Since more current must be applied than the power supply current, more power loss occurs, resulting in increased heat generation and reduced system efficiency.

In the conventional high voltage power supply circuit as shown in FIG. 7, when the sine wave high voltage Vac is applied to the HV terminal, the constant current Icc flows in all sections except for some low voltage sections. Accordingly, since the constant current flows between the HV terminal and the VCC pin, the VCC also shows a substantially constant voltage except for a portion of the AC low voltage section. At this time, since the power consumption generated by the Icc constant current source is the product of the HV terminal voltage and the Icc current, the power consumption form almost the same as that of the input sine wave as shown in Pd of FIG.

The problem is that since a constant current flows regardless of the input voltage level, a substantial amount of power is generated as heat losses, which contributes to IC operation and reliability as well as to system efficiency.

Accordingly, the present invention is to solve the above-described problems, the object of the present invention is to change the current value in accordance with the AC line voltage level, even if the same form of generating a power source by connecting directly to the IC at the AC high voltage stage It is to provide a high-voltage power supply circuit that improves the efficiency of preventing unnecessary power consumption and minimizing heat generation in a chip by controlling a variable current instead of a constant current to be supplied to an IC power supply.

First, to summarize the features of the present invention, according to an aspect of the present invention, the operation method of the power circuit inside the IC chip to generate and maintain a constant voltage using the input AC voltage, to reduce the power consumption inside the IC chip To this end, when the IC chip is supplied with an AC voltage, it is characterized by charging a capacitor outside the IC chip by varying the current value supplied according to the magnitude of the AC voltage.

According to another aspect of the present invention, a power supply circuit inside an IC chip for generating and maintaining a predetermined voltage using an input AC voltage may include: a Vac voltage sensing circuit configured to detect a magnitude of an input AC voltage; And an Icc variable control circuit configured to variably control a current value of a constant current source supplied with the input AC voltage according to the sensed magnitude of the AC voltage, and to control a capacitor outside the IC chip with a variable current from the constant current source. It is characterized by charging.

The Vcc voltage sensing circuit may further include a Vcc voltage sensing circuit configured to sense the magnitude of the voltage of the capacitor, and the Icc variable control circuit may control the current value of the constant current source so that the magnitude of the voltage of the capacitor is maintained within a predetermined range.

According to the magnitude of the AC voltage sensed in real time, by using the Icc variable control circuit, it is possible to increase the current value at a low voltage of the AC voltage and to decrease the current value toward the AC voltage high voltage.

And further comprising a diode for enabling the use of the AC voltage regardless of whether the AC voltage is a continuous waveform or a switching discontinuity waveform. When the voltage is lower than the capacitor, reverse current flow can be prevented.

The Vac voltage sensing circuit may detect a voltage obtained by dividing the AC voltage by two resistors connected in series between the input terminal and the ground terminal of the AC voltage.

Alternatively, the Vac voltage sensing circuit controls the on / off of the switch by a clock signal by using a first resistor, a switch, and a second resistor connected in series between the input terminal and the ground terminal of the AC voltage. The voltage obtained by dividing the AC voltage by the first resistor and the second resistor may be detected by sampling.

The Vac voltage sensing circuit may convert the sensed AC voltage into a digital value using an analog-digital converter, and the Icc variable control circuit may control the constant current source according to the digital value.

According to the high voltage power supply circuit according to the present invention, the AC line voltage is sensed in real time so that a relatively large value of current is supplied at an AC low voltage similar to that of the IC power voltage, and the higher the AC voltage, By reducing the amount, the average current supplied by the IC is the same, but power consumption and heat generation can be greatly reduced.

Accordingly, even when the corresponding pin of the IC is directly connected to the AC high voltage terminal, unnecessary power consumption of all the ICs receiving the power current can be minimized, and heat generation in the chip can be minimized. Improvements are possible. When developing an IC using a high voltage process, the power supply design can be made easier, and it can be designed to operate normally without adding a separate transformer auxiliary winding to supply power to the IC.

1 is a view for explaining the concept of a high-efficiency high voltage power supply circuit according to an embodiment of the present invention.
2 is a signal waveform illustrating characteristics of a high efficiency high voltage power supply circuit according to an embodiment of the present invention.
3 is an embodiment of a high efficiency high voltage power supply circuit according to an embodiment of the present invention.
4 is another embodiment of a high efficiency high voltage power supply circuit according to an embodiment of the present invention.
5 is another embodiment of a high efficiency high voltage power supply circuit according to an embodiment of the present invention.
6A, 6B and 6C illustrate a conventional high voltage power supply circuit.
7 is a graph for explaining the characteristics of the conventional high voltage power supply circuit.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout.

1 is a view for explaining the concept of a high-efficiency high voltage power supply circuit 100 according to an embodiment of the present invention.

Referring to FIG. 1, the high efficiency high voltage power supply circuit 100 according to an embodiment of the present invention includes a diode D, a constant current source 110 inside the IC chip, a Vac voltage sensing circuit 120, and a Vcc voltage sensing circuit. 130, and the Icc variable control circuit 140.

When a high external AC voltage Vac is applied to a predetermined pin of the IC chip, the Vac voltage sensing circuit 120 senses the magnitude of the AC voltage Vac passing through the high voltage diode D. The Icc variable control circuit 140 controls the constant current source 110 receiving the AC voltage Vac to adjust the current value Icc according to the magnitude of the sensed AC voltage Vac to generate the inside of the IC. The power consumption can be minimized.

As described above, while the constant current source 110 charges an external capacitor to generate a DC constant voltage Vcc in the capacitor while adjusting the amount of current, the voltage Vcc of the capacitor is rather than a constant voltage as shown in FIG. 2. AC ripple. Since the voltage Vcc of the capacitor moves within a predetermined operating voltage range for stable operation, the voltage Vcc of the capacitor may be sensed in real time, and thus the charging type may be changed according to the VCC voltage level. For example, the Vcc voltage sensing circuit 130 senses the magnitude of the voltage Vcc of the capacitor, and the Icc variable control circuit 140 also uses a constant current source according to the magnitude of the sensed voltage Vcc of the capacitor. 110 controls the current value Icc, that is, when the voltage Vcc of the capacitor increases above the preset voltage, the current value Icc of the constant current source 110 is adjusted to be small to control the VCC power supply. Control to prevent abnormal rise.

In addition, when the voltage Vcc of the capacitor falls below a predetermined operating range during normal operation, and the UVLO (Under Voltage Lockout) circuit (not shown) in the IC chip is operated, a malfunction of the capacitor results in malfunction. ) Can be compensated for this low voltage phenomenon. For example, when the magnitude of the voltage Vcc of the capacitor sensed by the Vcc voltage sensing circuit 130 is less than or equal to a specific voltage set higher than the UVLO voltage, the Icc variable control circuit 140 increases the current value Icc to a larger value. Controlling can suppress further discharge of the Vcc capacitor and enable stable operation to keep the voltage (Vcc) of the capacitor within its operating range.

The IC chip internal diode (D) connected to the pin receiving the external AC voltage (Vac) has a high voltage characteristic and two expected effects can be obtained by this diode (D). It prevents the current from flowing backward when the external AC voltage (Vac) is lower than the capacitor's voltage (Vcc), and almost 0V low voltage area that appears every cycle when the external AC voltage (Vac) is a non-sinusoidal switching waveform. This function prevents the reverse current flowing in the Vcc capacitor. Accordingly, the high voltage power supply circuit 100 of the present invention can be applied to both an external AC voltage Vac and a switching waveform (or pulse wave).

2 is a signal waveform for explaining the characteristics of the high efficiency high voltage power supply circuit 100 according to an embodiment of the present invention.

In FIG. 2, the external AC voltage Vac in the uppermost waveform exemplifies a high voltage waveform of a full-wave rectified sine wave, and in some cases, may be a half-wave rectified sine wave or a pulse wave.

Looking at the second waveform representing the current value Icc by the control of the Icc variable control circuit 140, the diode D is reversed in the low voltage section in which the AC voltage Vac is lower than the capacitor Vcc. Supply is interrupted. As the AC voltage Vac becomes larger than the voltage Vcc of the capacitor, it becomes possible to charge the capacitor with an Icc charging current, that is, a high level of current value Icc. Since the AC voltage (Vac) itself is low and the difference between the AC voltage and the capacitor (Vcc) is small, the amount of power consumed between the actual AC voltage (Vac) and the capacitor's voltage (Vcc) is increased even when the amount of capacitor charging current is increased. Extremely small When the voltage Vcc of the capacitor becomes higher than the maximum operating voltage, the difference between the AC voltage Vac and the Vcc voltage gradually increases, so that the Icc variable control circuit 140 charges the charge current value Icc to reduce heat generation due to unnecessary power consumption. Will gradually decrease. As the AC voltage (Vac) increases more and more, the Icc current value becomes smaller, and above a certain voltage it is possible to change the current value to a very low level or to reduce it to zero. At this time, the Vcc voltage correlates with the Vac voltage waveform and moves within the operating voltage range.

In this way, when adjusting the Icc current value according to the AC voltage (Vac) level, the average current becomes equal to or higher than the current level required by the IC chip internal circuit, and if the Vcc voltage does not exceed the operating voltage range, the existing constant current It guarantees the same IC operation as the supply method, while minimizing unnecessary power consumption and heat generation inside the IC chip. Under the principle that the charging current value Icc is increased in the low voltage region of the AC voltage Vac and the current value is reduced in the high voltage, a characteristic design having various shapes and values is possible.

3 is an embodiment of a high efficiency high voltage power supply circuit according to an embodiment of the present invention.

As shown in FIG. 3, the Vac voltage sensing circuit 120 receives a voltage obtained by dividing an AC voltage Vac by two resistors R1 and R2 connected in series between an AC voltage Vac input terminal and a ground terminal. Passive devices or active devices). This is the simplest and most reliable voltage sensing method.

4 is another embodiment of a high efficiency high voltage power supply circuit according to an embodiment of the present invention.

In this case, unnecessary power consumption is generated due to the current flowing through the two resistors R1 and R2, thereby improving the method of detecting the AC voltage Vac as shown in FIG. 3, which may cause a decrease in efficiency. As shown in FIG. 4, when the S / H (sample and hold) method is applied in conjunction with the clock signal CLK generated inside (or outside) the IC chip, voltage can be detected while minimizing unnecessary power consumption.

For example, as shown in FIG. 4, the switch is switched by a clock signal CLK using a first resistor R1, a switch, and a second resistor R2 connected in series between an AC voltage Vac input terminal and a ground terminal. Is turned on for a predetermined time, when the voltage obtained by dividing the AC voltage Vac by the two resistors R1 and R2 is sampled and temporarily stored in the S / H (sample and hold) 121, the Vac voltage sensing circuit ( 120 may detect the storage voltage of the S / H (sample and hold) 121 at a time synchronized with the clock signal CLK using predetermined elements (passive element or active element, etc.).

In this way, AC voltage (Vac) can be detected normally, and for most of the time except the detection time, the switch is turned off by the clock signal (CLK) to flow to the two resistors (R1, R2). You can make the current nearly zero. In this case, by adjusting the active time of the clock signal CLK, the average of the current values flowing through the second resistor R2 may be nearly zero.

5 is another embodiment of a high efficiency high voltage power supply circuit according to an embodiment of the present invention.

Although the AC voltage Vac may be sensed as shown in FIG. 4, which is a linear or simple non-linear control method, it may be implemented in a digital control method as shown in FIG. 5.

 For example, as shown in FIG. 5, the switch is switched by a clock signal CLK using a first resistor R1, a switch, and a second resistor R2 connected in series between an AC voltage Vac input terminal and a ground terminal. Is turned on for a predetermined time, the voltage obtained by dividing the AC voltage (Vac) by the two resistors (R1, R2) is sampled and temporarily stored in the S / H (sample and hold) 121, the Vac voltage sensing circuit ( The ADC (analog-to-digital converter) included in 120 detects the storage voltage of S / H (sample and hold) at a time synchronized with the clock signal CLK by using predetermined elements (passive element or active element, etc.) Can output as a digital value.

As described above, in the method of converting the sampled signal in conjunction with the clock signal CLK into a digital signal through the ADC, signal processing and processing are easy. In FIG. 4, the current Icc control value is determined depending on the sampled / held signal value each time. However, since the digital value of the AC voltage Vac sense voltage in FIG. The circuit 140 may nonlinearly control the magnitude of the Icc value. By calculating the root mean square (RMS) value of the input AC voltage (Vac), it is possible to appropriately control the size of each section or the current value (Icc) of the Icc charging graph according to the RMS value. Such a switch may be disposed at a different position in addition to the two resistors R1 and R2 to sample a voltage required for sensing when another element (passive element or active element, etc.) is used.

As can be seen from the representative circuit of FIG. 1 and the characteristic waveforms of FIG. 2 as described above, the high voltage power supply circuit of the present invention has the same form of generating power by connecting directly to an IC at an AC high voltage stage. By varying the current value according to the voltage level, a variable current rather than a constant current is controlled to be supplied to the IC power supply, thereby preventing unnecessary power consumption and minimizing heat generation in the chip.

In order to generate a VCC power supply without a separate auxiliary winding among general ICs using high voltage, a high voltage device such as a JFET is used to receive a constant current directly from a high voltage terminal such as an AC line. Since the IC is supplied with a current equal to or higher than the required current, there seems to be no problem in the IC operation, but in reality, the high voltage is applied between the high voltage terminal and the VCC outside the chip, resulting in a considerable power consumption.

For example, in the conventional circuit as shown in Fig. 6, in addition to the power normally consumed in the IC when Icc is designed to 1 mA, a loss of about 100 mW occurs when the AC voltage Vac is 110V. Also, at 220V, unnecessary power loss occurs around 200mW. This power loss is not just a loss, but a decrease in efficiency, which is caused by heat generation inside the chip, which adversely affects the operation characteristics, lifespan, and reliability of the IC.

On the other hand, applying the technology of the present invention as described above can minimize the unnecessary power consumption in addition to the power consumption required in the actual power supply of the IC can improve the IC operating characteristics, lifespan and reliability.

When the AC high voltage is applied to a predetermined pin of the IC chip, the Vac voltage detection circuit 120 checks the Vac voltage level inside the IC. Depending on the Vac voltage, the amount of current applied at high AC voltages can be adjusted to minimize power dissipation inside the IC.

In this way, if the charging current is varied according to the Vac voltage, the Vcc voltage shows AC ripple along the AC frequency rather than the constant voltage. Since the Vcc voltage needs to move within the specified operating voltage range, the Vcc voltage can also be detected in real time, and the charging type can be changed according to the Vcc voltage level. When the Vcc voltage increases above a predetermined voltage, the charging current value Icc may be adjusted small to prevent abnormal rise of the Vcc power supply. In addition, if the VLO voltage falls below the specified operating range during normal operation, and the UVLO (Under Voltage Lockout) circuit is operated, it may cause a malfunction. Therefore, the Vcc voltage is detected in real time to compensate for such low voltage phenomenon. When Vcc is below a certain voltage set higher than the UVLO voltage, increasing the Icc value to suppress further discharge of the VCC capacitor can result in stable operation within the VCC operating range.

By detecting the Vcc voltage in addition to the Vac voltage, circuit design work can estimate the current consumption inside the IC chip, but it may not be predictable how much the value of the external Vcc capacitor will be. In addition, the input Vac voltage may be a continuous waveform (sine wave, propagated / propagated sine wave, etc.) or a switching discontinuous waveform (or pulse wave). It is also considered that the amount of current supplied is changed. When the internal current consumption is fixed, the size of Vcc ripple varies depending on the type of external capacitor or Vac voltage, which can lead to an unstable operating range. Therefore, if the Vcc supply voltage is detected along with the Vac voltage, the optimal Icc current Value setting and stable operation can be guaranteed.

When the digital control method is applied together as shown in FIG. 5, more various control is possible. By analyzing the operation pattern, the optimum control value can be found for each system and operation environment. If the Vcc capacitor is sufficiently charged at a low voltage of Vac, further efficiency improvement is possible because the charging current value can be greatly reduced as the Vac voltage rises, which can be further controlled by real-time voltage sensing and more digitally controlled. This allows for more detailed control because iterative pattern analysis is possible.

At low voltages of Vac, it is possible to significantly increase the charge current into the Vcc capacitor in conjunction with the Vcc voltage rise. This is because when the voltage between Vac and Vcc is small, the resulting power consumption is also very small. When the Vac voltage is higher than the Vcc maximum operating voltage, the difference between Vac and Vcc increases gradually, so that the charging current is gradually reduced to reduce heat generation due to unnecessary power consumption. As the Vac voltage increases more and more, the Icc current value becomes smaller, and above a certain voltage it is possible to change the current value to a very low level or reduce it to zero.

In this way, when adjusting the Icc current value according to the Vac voltage level, if the average current is equal to or higher than the current level required by the IC internal circuit, and it does not exceed the operating voltage range, the same IC operation as the conventional constant current supply method is performed. This ensures minimum power dissipation and heat generation inside the IC chip. Including the above-described examples, designs having various shapes and values are possible under the basic principle of increasing the charge current value at low Vac and reducing the current value at high voltage.

As described above, the present invention has been described by way of limited embodiments and drawings, but the present invention is not limited to the above embodiments, and those skilled in the art to which the present invention pertains various modifications and variations from such descriptions. This is possible. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined by the equivalents of the claims, as well as the claims.

Claims (8)

In the operating method of the power supply circuit inside the IC chip to generate and maintain a constant voltage using the input AC voltage,
In order to reduce power consumption inside the IC chip,
When the IC chip is supplied with an AC voltage, a method of operating a power circuit, characterized by charging the capacitor outside the IC chip by varying the current value supplied according to the magnitude of the AC voltage. In a power supply circuit inside an IC chip that generates and maintains a constant voltage using an input AC voltage,
A Vac voltage sensing circuit sensing a magnitude of an input AC voltage; And an Icc variable control circuit for variably controlling the current value of the constant current source supplied with the input AC voltage according to the sensed magnitude of the AC voltage.
And a capacitor external to the IC chip with a variable current from the constant current source. The method of claim 2,
Further comprising a Vcc voltage sensing circuit for sensing the magnitude of the voltage of the capacitor,
And the Icc variable control circuit controls the current value of the constant current source so that the magnitude of the voltage of the capacitor is maintained within a predetermined range. The method of claim 2,
The power supply circuit according to the magnitude of the AC voltage sensed in real time, using the Icc variable control circuit, increasing the current value at a low voltage of the AC voltage, and decreases the current value toward the AC voltage high voltage. The method of claim 2,
It further comprises a diode for enabling the use of the AC voltage whether the continuous waveform or switching discontinuous waveform,
And an external AC voltage passing through the diode as the input AC voltage, thereby preventing current flow in reverse when the external AC voltage is lower than the voltage of the capacitor. The method of claim 2,
The Vac voltage sensing circuit detects a voltage obtained by dividing the AC voltage by two resistors connected in series between the input terminal and the ground terminal of the AC voltage. The method of claim 2,
The Vac voltage sensing circuit,
By using a first resistor, a switch, and a second resistor connected in series between the input terminal and the ground terminal of the AC voltage, the on / off of the switch is controlled by a clock signal, and the first and second resistors are used. A power supply circuit, characterized in that the AC voltage is detected by sampling the divided voltage. The method of claim 2,
The Vac voltage sensing circuit,
And converting the sensed AC voltage into a digital value using an analog-to-digital converter, and wherein the Icc variable control circuit controls the constant current source in accordance with the digital value.

Images