converter

Abstract

This invention provides a converter comprising a first converter and a second converter, wherein the first converter is used to transfer energy from a voltage source to a load, and the second converter receives a control signal from the load voltage to regulate the load voltage. The DC / DC converter of this invention can be a Sigma converter, a Delta converter, or a Sigma-Delta converter, and the specific operating mode can be selected according to the power supply voltage or the load voltage, wherein the power supply voltage or the load voltage varies over a wide range.

Description

Technical Field

[0001] This case relates to a DC / DC converter that maintains high efficiency over a wide input and output voltage range, and more particularly to a DC / DC converter that maintains high efficiency over a wide input and output voltage range and employs Sigma and Delta topologies. Background Technology

[0002] LLC resonant DC / DC converters (hereinafter referred to as "LLC converters") offer high efficiency in both high-voltage and low-voltage applications. High efficiency is achieved across the entire range of input voltage, output voltage, and load current through zero-voltage switching (ZVS) on the primary side and zero-current switching (ZCS) on the secondary side rectifier. The LLC converter achieves its highest efficiency when operating at its series resonant frequency. Due to significantly reduced switching losses, LLC converters can achieve higher power density when operating at high switching frequencies. Generally, LLC converters operate at variable switching frequencies when operating with variable input and output voltages. If the input or output voltage range is expanded (e.g., in applications requiring sustained-time operation (such as servers and network computers in data centers), high-voltage photovoltaic (PV) series applications, and on-board chargers), the switching frequency range will also expand, leading to a decrease in converter efficiency.

[0003] By employing the following existing technologies, the switching frequency range in applications with a wide input and output voltage range can be effectively reduced.

[0004] One existing technique controls the output voltage of an LLC converter by combining variable frequency feedback control and open-loop delay time (e.g., phase shift) control. This technique uses variable frequency control for the primary-side switching and delay time control for controlling the secondary-side synchronous rectifier. Thus, when the delay time control increases the energy in the resonant cavity, the LLC converter exhibits boost characteristics, meaning the delay time control increases the voltage gain of the LLC converter. This prior art has been disclosed in the following references: (1) US Patent 9,490,704 to Jang et al., entitled "System and method for controlling secondary-side switches inresonant power converters," issued on November 8, 2016; (2) the article, entitled "Series resonant converter with reduced frequency-range control," by Jang et al., published in Proc. IEEE Applied Power Electron.Conf.(APEC), 2015, pp.1453-1460; and (3) the article, entitled "A new LLC series resonant converter with anarrow switching frequency variation and reduced conduction losses," by J.WKim et al., published in IEEE Trans.Power Electron., vol.29, no.8, Aug.2014, pp.4278-4287.

[0005] Another existing technology involves adding an auxiliary DC / DC converter to the LLC converter. In this technology, the LLC converter and the auxiliary DC / DC converter can be connected in a Sigma or Delta topology and are referred to as an LLC DCX. The LLC DCX has high efficiency when operating at its ideal operating point, which can be, for example, a fixed switching frequency (i.e., its series resonant frequency) and a fixed duty cycle (e.g., close to 50%). Thus, the LLC DCX can deliver the majority of the output power, while the auxiliary DC / DC converter is used to regulate the output voltage and delivers only a small portion of the output power.

[0006] The LLC DCX, which uses Sigma topology, was originally designed for use in voltage regulator modules (VRMs) in server power supplies. The following references illustrate several LLC DCXs employing Sigma topology: (a) the article, entitled “High-efficiency quasi-parallel voltage regulator,” by J. Sun et al., published in Proc. IEEE Applied Power Electronics Conf. (APEC), 2008, pp. 811-817; (b) US Patent 7,872,9866 to M. Xu et al., entitled “Quasi-parallel voltage regulator,” issued on January 18, 2011; (c) the article, entitled “High-efficiency high-power density 48 / 1V sigma converter voltage regulator module” (“Ahmed”), by M. Ahmed et al., published in Proc. IEEE Applied Power Electronics Conf. (APEC), 2017, pp. 2207-2212.

[0007] Reference (c) discloses a converter employing a Sigma topology (hereinafter referred to as a "Sigma converter," or Σ converter or integral converter), which includes an unregulated LLC DCX and a regulated non-isolated auxiliary DC / DC converter. Figure 1 A schematic diagram of the Sigma converter (i.e., Sigma converter 100) from reference (c) is shown. Figure 1 As shown, in the Sigma converter 100, the input voltage V of LLC DCX 101 and auxiliary DC / DC converter 102 is... IN,DCX and V IN,AUX Each is composed of capacitor C DCX and C AUX The voltage provided on, and V IN,DCX and V IN,AUX The sum equals the power supply voltage V IN The capacitor C DCX and C AUXThey are connected in series. The output signals of LLC DCX 101 and the auxiliary DC / DC converter 102 are connected in parallel to capacitor C. O The LLCDCX 101 transmits the majority of the output power, and its primary-side switch and secondary-side synchronous rectifier operate at ZVS and ZCS respectively, thus exhibiting extremely high efficiency. Even though the auxiliary DC / DC converter 102 only transmits a small portion of the output power, it is used as a buck converter, where the buck converter employs pulse-width modulation (PWM) to regulate the output voltage V. O Therefore, the Sigma converter 100 has extremely high efficiency. Figure 2 It shows the use of Figure 1 Circuit 200 of Sigma converter 100.

[0008] Delta converters (hereinafter referred to as "Delta converters," or Δ converters) were originally used as intermediate bus converters in telecommunications power supply circuits. Several Delta converters are illustrated in the following references: (i) the article "A MHz regulated DC transformer with wide voltage range," by T. Liu et al., published in the Proc. IEEE Int'l PowerElectron. and Appl. Conf. (PEAC), 2018, pp. 794-797; and (ii) the article "1MHz 48V-12V regulated DCX with single transformer," by T. Liu et al., published in the IEEE Journal of Emerging and Selected Topics in Power Electronics, vol. 9, Issue 1, Feb. 2021. Similar to Sigma converters, Delta converters can consist of an unregulated LLC DCX and a regulated auxiliary DC / DC converter.

[0009] Figure 3 An existing Delta converter 300 is shown. Unlike the auxiliary DC / DC converter 102 in the Sigma converter 100, which provides the output voltage V, this converter... OWith a load, the auxiliary DC / DC converter 302 in the Delta converter 300 receives the input signal from the auxiliary output of the LLC DCX 301. The input voltage V of the LLC DCX 301 is... IN,DCX The series-connected power supply voltage V IN and capacitor C AUX Provided, that is, the input voltage V of the LLC DCX 301 IN,DCX Equal to the power supply voltage V IN With the output voltage V of the auxiliary DC / DC converter 302 O,AUX The sum. In other words, the name "Delta converter" means the input power supply voltage V. IN Equal to voltage V IN,DCX With V O,AUX The difference between them. In Delta converter 300, LLC DCX 301 transfers power to the load and also transfers the input power to auxiliary DC / DC converter 302. Auxiliary DC / DC converter 302 can be a non-isolated DC / DC converter (e.g., a buck converter) that operates under PWM to regulate the load voltage. Auxiliary DC / DC converter 302 is used to transfer only a small fraction of the load power. Therefore, Delta converter 300 also has extremely high efficiency. Figure 4 It shows the use of Figure 3 The circuit 400 of the Delta converter 300. In the Delta converter 300 (e.g. Figure 4 The circuit shown in Figure 400 has a power supply voltage of V. IN It is floating, meaning the power supply voltage V IN It is not connected to the primary side grounding terminal. Summary of the Invention

[0010] This application relates to a DC / DC converter that operates over a wide input and output voltage range, for example, in applications requiring sustained operating time (e.g., servers and network computers in data centers), high-voltage photovoltaic array applications, and DC / DC converters in on-board chargers with a wide input and output voltage range; or in high-power-density applications requiring high efficiency and high switching frequency.

[0011] This invention can be used with DC / DC converters having Sigma, Delta, or Sigma-Delta topologies. The Sigma, Delta, and Sigma-Delta converters of this invention are composed of two combined DC / DC converters. One of the DC / DC converters is an unregulated converter (e.g., an LLC converter, a series resonant converter (SRC), or a dual-active-bridge (DAB) converter). The other DC / DC converter is an auxiliary converter with an adjustable output voltage.

[0012] The Sigma topology in this Sigma converter can be configured on the voltage source side (i.e., as an input Sigma converter) or the load side (i.e., as an output Sigma converter). In the input Sigma converter, the sum of the input voltages of the two DC / DC converters equals the supply voltage; while in the output Sigma converter, the sum of the output voltages of the two DC / DC converters equals the load voltage. The Delta topology in this Delta converter is configured on the voltage source side.

[0013] The output Sigma and Delta converters of this invention exhibit the highest efficiency at the maximum supply voltage, with their efficiency decreasing slightly as the supply voltage decreases. The input Sigma converter, however, exhibits the highest efficiency at the minimum supply voltage, with its efficiency decreasing slightly as the supply voltage increases. Furthermore, compared to the Sigma or Delta converters, the Sigma-Delta converter of this invention achieves more balanced efficiency across the entire supply voltage range.

[0014] A further understanding of the invention can be gained through the following detailed description and corresponding drawings. Attached Figure Description

[0015] Figure 1 This is a block diagram of the existing Sigma converter 100.

[0016] Figure 2 It shows the use of Figure 1 The existing Sigma converter 100 circuit 200.

[0017] Figure 3 This is a block diagram of the existing Delta converter 300.

[0018] Figure 4 It shows the use of Figure 3 The existing Delta converter 300 circuit 400.

[0019] Figure 5This is a block diagram of an input Sigma converter 500 according to an embodiment of this case.

[0020] Figure 6 This illustrates an embodiment of the invention. Figure 5 Example circuit 600 for the input Sigma converter 500.

[0021] Figure 7 This is a block diagram of an output Sigma converter 700 according to an embodiment of this case.

[0022] Figure 8 This illustrates an embodiment of the invention. Figure 7 Example circuit 800 for the output Sigma converter 700.

[0023] Figure 9 This is a block diagram of an output Sigma converter 900 according to an embodiment of this case.

[0024] Figure 10 This illustrates an embodiment of the invention. Figure 9 Example circuit 1000 for the output Sigma converter 900.

[0025] Figure 11 This is a block diagram of an output Sigma converter 1100 according to an embodiment of this case.

[0026] Figure 12 This illustrates an embodiment of the invention. Figure 11 Example circuit 1200 for the output Sigma converter 1100.

[0027] Figure 13 This is a block diagram of an output Sigma converter 1300 according to an embodiment of this case.

[0028] Figure 14 This is a block diagram of an output Sigma converter 1400 according to an embodiment of this case.

[0029] Figure 15 This is a block diagram of a Delta converter 1500 according to an embodiment of this case.

[0030] Figure 16 This illustrates an embodiment of the invention. Figure 15 Example circuit 1600 for Delta converter 1500.

[0031] Figure 17 This is a block diagram of a Delta converter 1700 according to an embodiment of this case.

[0032] Figure 18 This illustrates an embodiment of the invention. Figure 17Example circuit 1800 for Delta converter 1700.

[0033] Figure 19 This is a block diagram of a Delta converter 1900 according to an embodiment of this case.

[0034] Figure 20 This illustrates an embodiment of the invention. Figure 19 The first example circuit of the Delta converter 1900 2000.

[0035] Figure 21 This illustrates an embodiment of the invention. Figure 19 The second example circuit 2100 of the Delta converter 1900.

[0036] Figure 22 This is a block diagram of a Delta converter 2200 according to an embodiment of this case.

[0037] Figure 23 This is a block diagram of a Delta converter 2300 according to an embodiment of this case.

[0038] Figure 24A This is a block diagram of a Sigma-Delta converter 2400 according to an embodiment of this case.

[0039] Figure 24B The efficiency of an input Sigma converter (e.g., converter 500), a Delta converter (e.g., converter 1500), and a Sigma-Delta converter 2400 operating with input voltages between VIN,min and VIN,max is shown.

[0040] Figure 25 This illustrates an embodiment of the invention. Figure 24A The first example circuit 2500 of the Sigma-Delta converter 2400.

[0041] Figure 26 This illustrates an embodiment of the invention. Figure 24A The second example circuit 2600 of the Sigma-Delta converter 2400.

[0042] Figure 27 This illustrates an embodiment of the invention. Figure 24A The third example circuit 2700 of the Sigma-Delta converter 2400.

[0043] Figure 28 This is a block diagram of a Sigma-Delta converter 2800 according to an embodiment of this case.

[0044] Figure 29This illustrates an embodiment of the invention. Figure 28 Example circuit 2900 for the Sigma-Delta converter 2800.

[0045] Figure 30 This is a block diagram of a Sigma-Delta converter 3000 according to an embodiment of this case.

[0046] Figure 31 This illustrates an embodiment of the invention. Figure 30 The first example circuit 3100 of the Sigma-Delta converter 3000.

[0047] Figure 32 This illustrates an embodiment of the invention. Figure 30 The second example circuit 3200 of the Sigma-Delta converter 3000.

[0048] Figure 33 This illustrates an embodiment of the invention. Figure 30 The third example circuit 3300 of the Sigma-Delta converter 3000.

[0049] The reference numerals in the attached figures are explained as follows:

[0050] 100: Sigma Converter

[0051] 101: LLC DCX

[0052] 102: Auxiliary DC / DC Converter

[0053] V IN,DCX V IN,AUX V O,AUX V O,DCX :Voltage

[0054] C DCX C AUX :capacitance

[0055] V IN Power supply voltage

[0056] C O C r :capacitance

[0057] V O :Voltage

[0058] Q1, Q2, Q3, Q4, Q5, Q6, Q7, Q8, Q9, Q 10 Q 11 Q 12 Q 13 Q 14 Q 15 Q16 :switch

[0059] L B L r L m :inductance

[0060] XF: Transformer

[0061] SR1, SR2, SR3, SR4, SR5, SR6, SR7: Rectifiers

[0062] I Load Load current

[0063] 200: Circuit

[0064] 201: LLC DCX

[0065] 202: Auxiliary DC / DC Converter

[0066] 300: Delta Converter

[0067] 301: LLC DCX

[0068] 302: Auxiliary DC / DC Converter

[0069] 400: Circuit

[0070] 401: LLC DCX

[0071] 402: Auxiliary DC / DC Converter

[0072] C O,AUX C IN,AUX :capacitance

[0073] N P N S N AUX Winding

[0074] TX: Transformer

[0075] R L :resistance

[0076] 500: Input Sigma Converter

[0077] 501: DCX Converter

[0078] 502: Auxiliary DC / DC Converter

[0079] 511, 514: Output terminals

[0080] 512, 513: Input terminals

[0081] 600: Example Circuit

[0082] 601: LLC DCX

[0083] TX DCX :transformer

[0084] 603a: Input terminal

[0085] 603b, 603c: Output terminals

[0086] 602: Boost Converter

[0087] L BB L r,AUX :inductance

[0088] C r,AUX :capacitance

[0089] V BB :Voltage

[0090] 700: Output Sigma Converter

[0091] 701: DCX Converter

[0092] 702: Auxiliary DC / DC Converter

[0093] V O,REF :Voltage

[0094] 800: Example Circuit

[0095] 801: LLC DCX

[0096] 802: Flyback Converter

[0097] XF DCX TX FLY :transformer

[0098] L mFLY :inductance

[0099] Q FLY :switch

[0100] N PF N SF Winding

[0101] SR FLY : Rectifier

[0102] V oFLY :Voltage

[0103] C Ofly C O,DCX :capacitance

[0104] 900: Output Sigma Converter

[0105] 901: DCX Converter

[0106] 902: Auxiliary DC / DC Converter

[0107] 1000: Example Circuit

[0108] 1001: LLC DCX

[0109] 1002: Buck-Boost Converter

[0110] SR BB : Rectifier

[0111] Q BB :switch

[0112] C BB :capacitance

[0113] 1100: Output Sigma Converter

[0114] 1101: DCX Converter

[0115] 1102: Auxiliary DC / DC Converter

[0116] V O1,DCX V O2,DCX :Voltage

[0117] 1200: Example Circuit

[0118] 1201: LLC DCX

[0119] 1202: Flyback Converter

[0120] 1204a, 1204b: Output terminals

[0121] 1300: Output Sigma Converter

[0122] 1301: DCX Converter

[0123] 1302: Auxiliary DC / DC Converter

[0124] 1305: Auxiliary voltage source

[0125] 1400: Output Sigma Converter

[0126] 1401: DCX Converter

[0127] 1402: Auxiliary DC / DC Converter

[0128] 1405: Auxiliary voltage source

[0129] 1500: Delta Converter

[0130] 1501: DCX Converter

[0131] 1502: Auxiliary DC / DC Converter

[0132] 1511, 1512, 1513: Output terminals

[0133] 1514: Input terminal

[0134] 1600: Example Circuit

[0135] 1601: LLC DCX

[0136] 1602: Buck-Boost Converter

[0137] 1611, 1612: Output terminals

[0138] 1614: Input terminal

[0139] 1700: Delta Converter

[0140] 1701: DCX Converter

[0141] 1702: Auxiliary DC / DC Converter

[0142] 1800: Example Circuit

[0143] 1801: LLC DCX

[0144] 1802: Buck-Boost Converter

[0145] V oBB :Voltage

[0146] 1900: Delta Converter

[0147] 1901: DCX Converter

[0148] 1902: Auxiliary DC / DC Converter

[0149] 2000: First Example Circuit

[0150] 2001: LLC DCX

[0151] 2002: Buck Converter

[0152] C B :capacitance

[0153] V O,BUCK :Voltage

[0154] L BUCK :inductance

[0155] Q BUCK :switch

[0156] SR BUCK : Rectifier

[0157] 2100: Second Example Circuit

[0158] 2101: LLC DCX

[0159] 2102: Flyback Converter

[0160] Q 1,FLY Q 2,FLY :switch

[0161] C FLY :capacitance

[0162] XF FLY :transformer

[0163] 2200: Delta Converter

[0164] 2201: DCX Converter

[0165] 2202: Auxiliary DC / DC Converter

[0166] 2203: Auxiliary voltage source

[0167] 2300: Delta Converter

[0168] 2301: DCX Converter

[0169] 2302: Auxiliary DC / DC Converter

[0170] 2303: Auxiliary voltage source

[0171] 2400: Sigma-Delta Converter

[0172] 2401: DCX Converter

[0173] 2402: Auxiliary DC / DC Converter

[0174] V AUX :Voltage

[0175] V IN,max Maximum power supply voltage

[0176] V IN,min Minimum power supply voltage

[0177] 2500: First Example Circuit

[0178] 2501: LLC DCX

[0179] 2502: Bidirectional buck / boost converter

[0180] 2511: Input terminal

[0181] 2512: Output terminal

[0182] 2521: Second-level structure

[0183] 2522: First-level structure

[0184] TX AUX :transformer

[0185] N P,AUX N S,AUX Winding

[0186] 2600: Second Example Circuit

[0187] 2601: LLC DCX

[0188] 2602: Flyback Converter

[0189] 2611: Input terminal

[0190] 2612: Output terminal

[0191] D5, D6, D7: Diodes

[0192] 2700: Third Example Circuit

[0193] 2701: LLC DCX

[0194] 2702: Flyback Converter

[0195] 2800: Sigma-Delta Converter

[0196] 2801: DCX Converter

[0197] 2802: Auxiliary DC / DC Converter

[0198] 2900: Example Circuit

[0199] 2901: LLC DCX

[0200] 2902: Buck-Boost Converter

[0201] 3000: Sigma-Delta Converter

[0202] 3001: DCX Converter

[0203] 3002: Auxiliary DC / DC Converter

[0204] 3011: Input terminal

[0205] 3100: First Example Circuit

[0206] 3101: LLC DCX

[0207] 3102: Buck-Boost Converter

[0208] 3200: Second Example Circuit

[0209] 3201: LLC DCX

[0210] 3202: Flyback Converter

[0211] 3300: Third Example Circuit

[0212] 3301: LLC DCX

[0213] 3302: Flyback Converter Detailed Implementation

[0214] Some typical embodiments that embody the features and advantages of this invention will be described in detail in the following description. It should be understood that this invention can have various variations in different forms, all of which do not depart from the scope of this invention, and the descriptions and illustrations therein are for illustrative purposes only and are not intended to limit this invention.

[0215] The DC / DC converter of this invention comprises two components: (i) an unregulated DC / DC converter; and (ii) a DC / DC converter with an adjustable output voltage. In the following detailed description, the unregulated DC / DC converter will be referred to as the "DCX converter," and the DC / DC converter with an adjustable output voltage will be referred to as the "auxiliary DC / DC converter." As will be apparent from the detailed description, this invention is particularly advantageous for applications with wide input or output voltage ranges. For example, in computer applications requiring sustained operation (e.g., servers and network computers in data centers), the power supply voltage V of the DC / DC converter... IN This could be the output voltage of a power factor correction (PFC) circuit. In this application, the input voltage V... IN The apparent value is, for example, 380±20V, but in special cases it may vary between 200-400V. To ensure data integrity, for example during an orderly shutdown procedure (approximately 10-100 milliseconds), the output voltage V at the load must be kept constant. O Essentially, it is maintained at a fixed value (e.g., 48±5V). In this example, the DCX converter should primarily be responsible for transferring virtually all the power to the load, while the auxiliary DC / DC converter maintains the output voltage V. OMaintaining stability. To achieve this, the DCX converter can operate at 2kW, while the auxiliary DC / DC converter can operate at 300W. The DCX converter is preferably equipped with an isolation transformer, the turns ratio of which essentially determines its relatively fixed gain.

[0216] The Sigma topology in the Sigma converter of this case can be set on the voltage source side (i.e., as an input Sigma converter) or the load side (i.e., as an output Sigma converter). Figure 5 This is a block diagram of an input Sigma converter 500 according to an embodiment of this case. Figure 5 As shown, the input Sigma converter 500 includes a DCX converter 501 (e.g., an LLC converter, a series resonant converter, or a dual active bridge converter). The auxiliary DC / DC converter 502 can be a regulated, non-isolated auxiliary DC / DC converter. For example... Figure 5 As shown, the input terminals 512 and 513 of the DCX converter 501 and the auxiliary DC / DC converter 502 are connected in series with capacitors C. DCX and C AUX Therefore, its input voltage V represents... IN,DCX and V IN,AUX The sum equals the power supply voltage V IN In this architecture, if the input voltage V of DCX converter 501... IN,DCX It is essentially a constant value (and less than the power supply voltage V). IN If the minimum value is reached, then the input voltage V of the auxiliary DC / DC converter 502 is... IN,AUX With power supply voltage V IN Rising together, i.e., V IN,AUX =V IN -V IN,DCX The DCX converter 501 has output terminals 511 and 514, where output terminal 511 delivers power to the load, and output terminal 514 (also referred to as "auxiliary output terminal 514") is the common connection terminal between the DCX converter 501 and the auxiliary DC / DC converter 502. The auxiliary DC / DC converter 502 can be a non-isolated DC / DC converter operating under PWM (e.g., a buck converter, a boost converter, or a buck-boost converter) to regulate the voltage V across the load. OEven if a small portion of the load power can be transferred from input 512 to output 514 of auxiliary DC / DC converter 502, DCX converter 501 receives power at input 513 and transfers virtually all power to the load. Since inputs 513 and 512 of DCX converter 501 and auxiliary DC / DC converter 502 are connected in series, power is distributed across DCX converter 501 and auxiliary DC / DC converter 502 according to the input voltage ratio, i.e., P... IN,DCX / P IN,AUX =V IN,DCX / V IN,AUX , where P IN,DCX and P IN,AUX These represent the power received by DCX converter 501 and auxiliary DC / DC converter 502, respectively. When the power supply voltage V... IN Its minimum value, and the input voltage V of DCX converter 501 IN,DCX When the input voltage V- is constant, IN,AUX It has its minimum value, therefore Figure 5 The input Sigma converter 500 operates at a power supply voltage of V. IN It has the highest efficiency when its value is minimized.

[0217] Figure 6 This illustrates an embodiment of the invention. Figure 5 Example circuit 600 for the input Sigma converter 500. Figure 6 In this implementation, LLC DCX 601 is used. Figure 5 The DCX converter 501, LLC DCX601 contains a transformer located at the TX DCX The primary side input terminal 603a and located at the transformer TX DCX The secondary side output terminals 603b and 603c are used. Input terminals 603a, output terminals 603b, and auxiliary output terminals 603c all use a full-bridge topology; however, this is not a limitation, a half-bridge topology can also be used. Furthermore, in the LLC DCX 601, the transformer TX... DCX Each output terminal on the secondary side can also be formed by a center-tapped secondary winding and two synchronous rectifiers. Figure 6 In this implementation, a boost converter 602 is used. Figure 5 The 502 is a non-isolated auxiliary DC / DC converter. Figure 5 The non-isolated auxiliary DC / DC converter 502 is not limited to this and can also be implemented with converters of other topologies (such as buck converters or buck-boost converters).

[0218] Figure 7This is a block diagram of an output Sigma converter 700 according to an embodiment of this invention. The output Sigma converter 700 includes: (i) an isolated DCX converter 701 (e.g., an LLC converter, a series resonant converter, or a dual active bridge converter); and (ii) a regulated isolated auxiliary DC / DC converter 702. The outputs of the DCX converter 701 and the auxiliary DC / DC converter 702 are connected in series, such that their respective output voltages V O,DCX and V O,AUX The sum of the voltages equals the output voltage V. O The input terminals of DCX converter 701 and auxiliary DC / DC converter 702 are connected in parallel to the input power supply voltage V. IN In the DCX converter 701, the primary-side switch operates under ZVS conditions, and the secondary-side rectifier operates under ZCS conditions to achieve high efficiency. The auxiliary DC / DC converter 702 operates under PWM to regulate the output voltage V. O Although the efficiency of the auxiliary DC / DC converter 702 is lower than that of the DCX converter 701, the DCX converter 701 transfers the vast majority of its output power to the load, while the auxiliary DC / DC converter 702 transfers only a small portion of its output power to the load. Therefore, Figure 7 The output Sigma converter 700 achieves extremely high efficiency. Since the voltage gain of the DCX converter 701 is essentially constant, the output voltage V of the DCX converter 701... O,DCX The change in voltage and the power supply voltage V IN The change is proportional to the change in output voltage V. O,DCX Less than the output voltage V O Therefore, when the power supply voltage V IN When rising, the output voltage V of the auxiliary DC / DC converter 702 O,AUX The power decreases. Since the outputs of DCX converter 701 and auxiliary DC / DC converter 702 are connected in series, the power is distributed between DCX converter 701 and auxiliary DC / DC converter 702 according to their output voltage ratio, i.e., P... O,DCX / P O,AUX =V O,DCX / V O,AUX , where P O,DCX and P O,AUX These represent the power output to the load from the DCX converter 701 and the auxiliary DC / DC converter 702, respectively. When the power supply voltage V... IN When it reaches its maximum value, the output voltage V O,DCX It has its maximum value, and the output voltage V- O,AUX It has its minimum value. Therefore, Figure 7The output of the Sigma converter 700 at a supply voltage of V IN It is most efficient when it reaches its maximum value.

[0219] Figure 8 This illustrates an embodiment of the invention. Figure 7 Example circuit 800 of the output Sigma converter 700. Figure 8 In the middle, it is implemented using LLC DCX 801. Figure 7 The DCX converter 701, LLC DCX801 has a transformer XF DCX The full-bridge topology on the primary side and located at transformer XF DCX The secondary side has a center-tapped secondary winding and two synchronous rectifiers. However, this invention is not limited to this; the LLC DCX 801 can also be modified to have a secondary winding located at transformer XF. DCX The half-bridge topology on the primary side and located in transformer XF DCX The secondary winding of a single transformer is combined with a full-bridge rectifier. Furthermore, at... Figure 8 In this implementation, a flyback converter 802 is used. Figure 7 The isolated auxiliary DC / DC converter 702 is mentioned.

[0220] Figure 9 This is a block diagram of an output Sigma converter 900 according to an embodiment of this case. Figure 9 The output Sigma converter 900 includes: (i) an unregulated DCX converter 901 (e.g., an LLC converter, a series resonant converter, or a dual active bridge converter); and (ii) a regulated, non-isolated auxiliary DC / DC converter 902. The outputs of the DCX converter 901 and the auxiliary DC / DC converter 902 are connected in series, such that their respective output voltages Vi are equal. O,DCX and V O,AUX The sum of the voltages equals the output voltage V. O The input terminal of the DCX converter 901 is connected to the input power supply voltage V. IN The input of the auxiliary DC / DC converter 902 is connected to the output of the DCX converter 901. When transformer isolation is implemented in the DCX converter 901, the primary-side switch of the DCX converter 901 operates under ZVS conditions, and the secondary-side rectifier of the DCX converter 901 operates under ZCS conditions, thus achieving extremely high efficiency. The auxiliary DC / DC converter 902 operates under PWM to regulate the output voltage V. O Although the efficiency of the auxiliary DC / DC converter 902 is lower than that of the DCX converter 901, Figure 9The output Sigma converter 900 achieves extremely high efficiency. In fact, the DCX converter 901 directly transmits the vast majority of the output power, while the auxiliary DC / DC converter 902 only indirectly transmits a small portion. Since the voltage gain of the DCX converter 901 is essentially constant, the output voltage V of the DCX converter 901... O,DCX The change in voltage and the power supply voltage V IN The change is proportional to the change in output voltage V. O,DCX Less than the output voltage V O Therefore, when the power supply voltage V IN When rising, the output voltage V of the auxiliary DC / DC converter 902 O,AUX The output current of DCX converter 901 is equal to the sum of the load current and the input current of auxiliary DC / DC converter 902, while the output current of auxiliary DC / DC converter 902 is equal to the load current. Therefore, based on the output voltage V of DCX converter 901 and auxiliary DC / DC converter 902... O,DCX and V O,AUX The power is distributed across the DCX converter 901 and the auxiliary DC / DC converter 902, i.e., P O,DCX / P O,AUX =V O,DCX / V O,AUX +1 / η AUX , where η AUX To improve the efficiency of the DC / DC converter 902, P O,DCX and P O,AUX These represent the output power of DCX converter 901 and auxiliary DC / DC converter 902, respectively. When the power supply voltage V... IN At its maximum value, the output voltage V of DCX converter 901 O,DCX It has its maximum value, and the output voltage V- of the auxiliary DC / DC converter 902 O,AUX It has its minimum value. Therefore, Figure 9 The output of the Sigma converter 900 at a supply voltage of V IN It is most efficient when it reaches its maximum value.

[0221] Figure 10 This illustrates an embodiment of the invention. Figure 9 Example circuit 1000 of the output Sigma converter 900. Figure 10 In this case, it is implemented using LLC DCX 1001. Figure 9The DCX converter 901, LLC DCX 1001, has a full-bridge topology located on the primary side of transformer XF and a center-tapped winding and two synchronous rectifiers located on the secondary side of transformer XF. However, this invention is not limited to this; the LLC DCX1001 can also be modified to have a half-bridge topology located on the primary side of transformer XF and a single secondary winding and a full-bridge rectifier located on the secondary side of transformer XF. Furthermore, in... Figure 10 In this embodiment, a buck-boost converter 1002 is used. Figure 9 The non-isolated auxiliary DC / DC converter 902 is mentioned.

[0222] Figure 11 This is a block diagram of an output Sigma converter 1100 according to an embodiment of this invention. The output Sigma converter 1100 includes: (i) an unregulated DCX converter 1101 (e.g., an LLC converter, a series resonant converter, or a dual active bridge converter); and (ii) a regulated, non-isolated auxiliary DC / DC converter 1102. In the output Sigma converter 1100, the auxiliary DC / DC converter 1102 is powered by the second output of the DCX converter 1101, thereby enabling design optimization.

[0223] Figure 12 This illustrates an embodiment of the invention. Figure 11 Example circuit 1200 of the output Sigma converter 1100. Figure 12 In this case, it is implemented using LLC DCX 1201. Figure 11 The DCX converter 1101, LLC DCX 1201 has a full-bridge topology on the primary side of transformer TX and two output terminals 1204a and 1204b on the secondary side of transformer TX, wherein each output terminal includes a center-tapped secondary winding and two synchronous rectifiers. However, this invention is not limited thereto; in LLC DCX 1201, the primary side of transformer TX can also be a half-bridge topology, and each output terminal 1204a and 1204b on the secondary side of transformer TX can also be modified to include a single secondary winding and a full-bridge rectifier. Furthermore, in... Figure 12 In the middle, the flyback converter 1202 is implemented. Figure 11 The non-isolated auxiliary DC / DC converter 1102 is mentioned. It should be noted that... Figure 11 The non-isolated auxiliary DC / DC converter 1102 can also be implemented with converters of other topologies (e.g., boost converters or non-inverting buck-boost converters).

[0224] Figure 13This is a block diagram of an output Sigma converter 1300 according to an embodiment of the present invention. The output Sigma converter 1300 includes: (i) an unregulated DC-X converter 1301 (e.g., an LLC converter, a series resonant converter, or a dual active bridge converter); and (ii) a regulated non-isolated auxiliary DC / DC converter 1302. In the output Sigma converter 1300, the auxiliary DC / DC converter 1302 may be powered by an auxiliary voltage source 1305, wherein the auxiliary voltage source 1305 may, for example, be located on the output (i.e., load) side of the output Sigma converter 1300.

[0225] Figure 14 This is a block diagram of an output Sigma converter 1400 according to an embodiment of the present invention. The output Sigma converter 1400 includes: (i) an unregulated DCX converter 1401 (e.g., an LLC converter, a series resonant converter, or a dual active bridge converter); and (ii) a regulated isolated auxiliary DC / DC converter 1402. In the output Sigma converter 1400, the auxiliary DC / DC converter 1402 may be powered by an auxiliary voltage source 1405, wherein the auxiliary voltage source 1405 may, for example, be located on the input side (i.e., the input voltage source) of the output Sigma converter 1400.

[0226] The Delta converter provided in this case has two DC / DC converter components, and its Delta topology is set on the voltage source side.

[0227] Figure 15 This is a block diagram of a Delta converter 1500 according to an embodiment of this case. Figure 15 The Delta converter 1500 includes: (i) an unregulated DCX converter 1501 (e.g., an LLC converter, a series resonant converter, or a dual active bridge converter); and (ii) a regulated auxiliary DC / DC converter 1502. The DCX converter 1501 has outputs 1511 and 1512, where output 1511 is connected to a load, and output 1512 (i.e., the auxiliary output) is connected to the input of the auxiliary DC / DC converter 1502. The auxiliary DC / DC converter 1502 has an output 1513 (with capacitor C...). AUX (Indicated) is connected in series to the input terminal 1514 of the DCX converter 1501 (with capacitor C) DCX (represented), so that their respective voltages V IN,DCX and V O,AUX The voltage difference between them is equal to the power supply voltage V. INThe DCX converter 1501 transfers virtually all power to the load and the input power of the auxiliary DC / DC converter 1502. The auxiliary DC / DC converter 1502 can be a non-isolated DC / DC converter (e.g., a buck converter, boost converter, or buck-boost converter) and operates under PWM to regulate the load voltage. The power transferred by the auxiliary DC / DC converter 1502 is only a fraction of the load power. Therefore, the Delta converter 1500 has extremely high efficiency. The input voltage V of the DCX converter 1501... IN,DCX It is essentially a constant value and greater than the power supply voltage V. IN The maximum value, and the output voltage V of the auxiliary DC / DC converter 1502. O,AUX Equal to voltage difference V IN,DCX -V IN Therefore, the output voltage V of the auxiliary DC / DC converter 1502 O,AUX With power supply voltage V IN The output power P transferred by the DCX converter 1501 to the load increases as the load decreases. O The output power P transmitted from DCX converter 1501 to the input of auxiliary DC / DC converter 1502 IN,AUX The ratio P between them O / P IN,AUX and power supply voltage V IN With the output voltage V of the auxiliary DC / DC converter 1502 O,AUX The ratio between them is directly proportional, meaning P O / P IN,AUX ≈V IN / V O,AUX When the power supply voltage V IN When it reaches its maximum value, the voltage V O,AUX It has its minimum value, therefore Figure 15 The Delta converter 1500 operates at a power supply voltage of V. IN It is most efficient when it reaches its maximum value.

[0228] Figure 16 This illustrates an embodiment of the invention. Figure 15 Example circuit 1600 for the Delta converter 1500. Figure 16 In this implementation, LLC DCX 1601 is used. Figure 15The LLC DCX1601 DCX converter has an input terminal 1614, an auxiliary output terminal 1612, and an output terminal 1611. The input terminal 1614 is a full-bridge topology located on the primary side of the transformer TX. The auxiliary output terminals 1612 and 1611 are located on the secondary side of the transformer TX, and each output terminal includes a center-tapped winding and two synchronous rectifiers. However, this invention is not limited to this; in the LLC DCX 1601, the input terminal on the primary side of the transformer TX can also be a half-bridge topology, and each output terminal 1611 and 1612 on the secondary side of the transformer TX can also be modified to include a single secondary winding and a full-bridge rectifier. Furthermore, in... Figure 16 In this embodiment, a buck-boost converter 1602 is used. Figure 15 The non-isolated auxiliary DC / DC converter 1502 is mentioned. It should be noted that... Figure 15 The non-isolated auxiliary DC / DC converter 1502 can also be implemented with converters of other topologies (e.g., buck converters or boost converters).

[0229] Figure 17 This is a block diagram of a Delta converter 1700 according to an embodiment of this case. Figure 17 The Delta converter 1700 includes a DCX converter 1701 and an auxiliary DC / DC converter 1702, wherein the auxiliary DC / DC converter 1702 receives the input power supply voltage V. IN .

[0230] Figure 18 This illustrates an embodiment of the invention. Figure 17 Example circuit 1800 for the Delta converter 1700. Figure 18 In the middle, it is implemented using LLC DCX 1801. Figure 17 The DCX converter 1701, LLC DCX1801, has a full-bridge topology at its input on the primary side of transformer XF. The output on the secondary side of transformer XF includes a center-tapped secondary winding and two synchronous rectifiers. However, this invention is not limited to this; the input on the primary side of transformer XF in LLC DCX 1801 can also be a half-bridge topology, and the output on the secondary side of transformer XF can be modified to include a single winding and a full-bridge rectifier. Furthermore, in... Figure 18 In this implementation, a buck-boost converter 1802 is used. Figure 17 The non-isolated auxiliary DC / DC converter 1702 is mentioned.

[0231] Figure 19This is a block diagram of a Delta converter 1900 according to an embodiment of this invention. The Delta converter 1900 includes a DCX converter 1901 and a non-isolated auxiliary DC / DC converter 1902, wherein the non-isolated auxiliary DC / DC converter 1902 is powered by the input voltage V of the DCX converter 1901. IN,DCX powered by.

[0232] Figure 20 This illustrates an embodiment of the invention. Figure 19 The first example circuit of the Delta converter 1900 2000, Figure 21 This illustrates an embodiment of the invention. Figure 19 The second example circuit 2100 of the Delta converter 1900. Figure 20 and Figure 21 In this case, LLC DCX 2001 and 2101 were implemented respectively. Figure 19 The LLC DCX converter 1901. In the LLC DCX 2001, the input terminal 2011 on the primary side of the transformer TX has a full-bridge topology, and the output terminal 2012 on the secondary side of the transformer TX includes a center-tapped secondary winding and two synchronous rectifiers. However, this invention is not limited to this; the input terminal 2011 on the primary side of the transformer TX in the LLC DCX 2001 can also be a half-bridge topology, and the output terminal 2012 on the secondary side of the transformer TX in the LLC DCX 2001 can also be modified to include a single secondary winding and a full-bridge rectifier. Furthermore, in... Figure 20 In this implementation, a step-down converter 2002 is used. Figure 19 The non-isolated auxiliary DC / DC converter 1902.

[0233] Figure 21 The second example circuit 2100 includes LLC DCX 2101, wherein the structure of LLC DCX 2101 is substantially the same as... Figure 20 The LLC DCX 2001 is the same. Figure 21 In this implementation, a non-isolated flyback converter 2102 is used. Figure 19 The non-isolated auxiliary DC / DC converter 1902.

[0234] Figure 22 This is a block diagram of a Delta converter 2200 according to an embodiment of the present invention. The Delta converter 2200 includes a DCX converter 2201 and a non-isolated auxiliary DC / DC converter 2202, wherein the auxiliary DC / DC converter 2202 is powered by an auxiliary voltage source 2203 located on the input (i.e., input voltage source) side of the Delta converter 2200.

[0235] Figure 23This is a block diagram of a Delta converter 2300 according to an embodiment of the present invention. The Delta converter 2300 includes a DCX converter 2301 and an isolated auxiliary DC / DC converter 2302, wherein the isolated auxiliary DC / DC converter 2302 is powered by an auxiliary voltage source 2303 located on the load side of the Delta converter 2300.

[0236] As can be seen from the above embodiments, the input Sigma converter reaches its highest efficiency when the input voltage is at its minimum, and its efficiency decreases as the input voltage increases. Unlike the input Sigma converter, the Delta converter reaches its highest efficiency when the input voltage is at its maximum, and its efficiency decreases as the input voltage decreases. Therefore, by combining an input Sigma converter and a Delta converter, the combined Sigma-Delta converter exhibits more balanced high efficiency over a wide power supply voltage range compared to a single input Sigma converter or Delta converter.

[0237] Figure 24A This is a block diagram of a Sigma-Delta converter 2400 according to an embodiment of this invention. The Sigma-Delta converter 2400 includes: (i) an unregulated isolated DC-X converter 2401 (e.g., an LLC converter, a series resonant converter, or a dual active bridge converter); and (ii) a regulated bidirectional isolated auxiliary DC / DC converter 2402. It should be noted that the voltage V of the auxiliary DC / DC converter 2402 located on the input power supply voltage side... AUX It is bidirectional, i.e., V AUX It can be a positive or negative value.

[0238] Sigma-Delta converters (e.g.) Figure 24A The Sigma-Delta converter 2400 shown can operate in either Sigma or Delta mode. When operating in Sigma mode, the auxiliary DC / DC converter transfers power from the input voltage source to the load; therefore, the end of the auxiliary DC / DC converter connected in series with the input of the DCX converter is considered the input. In this architecture, the sum of the input voltages of the DCX converter and the auxiliary DC / DC converter, V... IN,DCX +V AUX Equal to the power supply voltage V INSimultaneously, the output of the DCX converter and the bidirectional terminal (as output) of the auxiliary DC / DC converter are connected in parallel to the load. When the DCX converter is isolated by a transformer, the primary-side switch in the DCX converter operates under ZVS conditions, and the secondary-side rectifier in the DCX converter operates under ZCS conditions. Therefore, the DCX converter has extremely high efficiency. The auxiliary DC / DC converter can operate under PWM to regulate the load voltage. Although the efficiency of the auxiliary DC / DC converter is lower than that of the DCX converter (where the DCX converter transfers the vast majority of the output power, while the auxiliary DC / DC converter transfers only a small portion of the output power), the Sigma-Delta converter operating in Sigma mode has extremely high efficiency. When operating in Sigma mode, the input voltage V of the DCX converter... IN,DCX Essentially a fixed value and less than the minimum power supply voltage, the input voltage V of the auxiliary DC / DC converter. AUX (=V IN –V IN,DCX With the power supply voltage V IN The power increases with the input voltage ratio of the DCX converter and the auxiliary DC / DC converter. Power is distributed between the DCX converter and the auxiliary DC / DC converter, i.e., P... IN,DCX / P IN,AUX =V IN,DCX / V AUX , where P IN,DCX and P IN,AUX These represent the power transferred by the DCX converter and the auxiliary DC / DC converter, respectively. When the power supply voltage V... IN When it reaches its minimum value, the input voltage V of the auxiliary DC / DC converter AUX It has its minimum value, and the input voltage V- of the DCX converter IN,DCX Essentially a constant value, therefore, a Sigma-Delta converter operating in Sigma mode will operate at a constant supply voltage V. IN It achieves its highest efficiency at its minimum value. In the aforementioned example (i.e., in a computer system with sustaining time requirements), the Sigma-Delta converter can operate at a supply voltage V... IN When the voltage is above 300V, it operates in Sigma mode.

[0239] When the Sigma-Delta converter operates in Delta mode, the auxiliary DC / DC converter transfers power from the load side to the input voltage source side. Therefore, the end of the auxiliary DC / DC converter connected in series with the input of the DCX converter is considered the output. In this architecture, the voltage difference V between the input of the DCX converter and the output of the auxiliary DC / DC converter is... IN,DCX -V AUX Equal to the power supply voltage VIN The output of the DCX converter and the bidirectional input of the auxiliary DC / DC converter are connected in parallel to the load. When the DCX converter is isolated by a transformer, the primary-side switch in the DCX converter operates under ZVS conditions, and the secondary-side rectifier in the DCX converter operates under ZCS conditions. Therefore, the DCX converter has extremely high efficiency. The auxiliary DC / DC converter can operate under PWM to regulate the load voltage. When operating in Delta mode, the DCX converter transfers power to the load and the auxiliary DC / DC converter. Although the efficiency of the auxiliary DC / DC converter is lower than that of the DCX converter, the power transferred by the auxiliary DC / DC converter is not substantially related to the output power at the load. Therefore, the Sigma-Delta converter operating in Delta mode still has extremely high efficiency. Because the input voltage V of the DCX converter... IN,DCX It is essentially a constant value and greater than the power supply voltage V. IN The maximum value, therefore the output voltage V of the auxiliary DC / DC converter AUX (=V IN,DCX –V IN With the power supply voltage V IN The power increases as the input voltage decreases. Based on the input voltage ratio, power is distributed across the load and the auxiliary DC / DC converter, i.e., P... O / P IN,AUX =V IN / V AUX , where P O and P IN,AUX These represent the power transferred from the DCX converter to the load and the auxiliary DC / DC converter, respectively. When the supply voltage V... IN When it reaches its minimum value, the voltage V AUX Having its minimum value, the Sigma-Delta converter operating in Delta mode has a supply voltage V IN It achieves its highest efficiency at its maximum value. In the aforementioned example (i.e., in a computer system with sustaining time requirements), the Sigma-Delta converter can operate at a supply voltage V... IN It operates in Delta mode when the voltage is below 300V.

[0240] Figure 24B It shows that it is between V IN,min With V IN,max The efficiency of input Sigma converters (e.g., converter 500), Delta converters (e.g., converter 1500), and Sigma-Delta converters 2400 operating between input voltages. Figure 24BIn the diagram, solid line 2451 represents the efficiency of the input Sigma (Σ) converter, solid line 2452 represents the efficiency of the Delta (Δ) converter, and dashed line 2453 represents the efficiency of the Sigma-Delta (Σ / Δ) converter. As shown by solid line 2451, the efficiency of the input Sigma converter at the minimum supply voltage V... IN,min The efficiency is highest at the lowest possible voltage, and decreases as the supply voltage increases. Therefore, the input Sigma converter operates at its highest possible supply voltage V. IN,max The Delta converter exhibits its lowest efficiency at the maximum supply voltage V0. As shown by solid line 2452, the Delta converter has the lowest efficiency at the maximum supply voltage V0. IN,max The Delta converter achieves its highest efficiency at the minimum supply voltage V, and its efficiency decreases as the supply voltage decreases. Therefore, the Delta converter operates at the minimum supply voltage V. IN,min The Sigma-Delta converter exhibits the lowest efficiency at an input voltage V0. As shown by dashed line 2453, the Sigma-Delta converter has the lowest efficiency at an input voltage V0. IN,DCX It has the highest efficiency at the designed input voltage V. IN,DCX V can be IN,min With V IN,min Any voltage between [variable values]. When the power supply voltage V... IN Greater than V IN,DCX At this time, the Sigma-Delta converter operates in Sigma mode. In Sigma mode, the Sigma-Delta converter operates at the input voltage V. IN,DCX The Sigma-Delta converter achieves its highest efficiency at the lowest possible supply voltage, and its efficiency decreases as the supply voltage increases. Therefore, the Sigma-Delta converter operates at its highest supply voltage V0. IN,max It has the lowest efficiency at this point. When the power supply voltage V IN Less than V IN,DCX At this time, the Sigma-Delta converter operates in Delta mode. In Delta mode, the Sigma-Delta converter operates at the input voltage V. IN,DCX The Sigma-Delta converter achieves its highest efficiency at the minimum supply voltage V, and its efficiency decreases as the supply voltage decreases. Therefore, the Sigma-Delta converter operates at the minimum supply voltage V. IN,min The lowest efficiency is achieved at this point. The maximum efficiency point of the Sigma-Delta converter can be adjusted based on the specific application.

[0241] Figure 25 This illustrates an embodiment of the invention. Figure 24A The first example circuit 2500 of the Sigma-Delta converter 2400. Figure 25 In this implementation, LLC DCX 2501 is used. Figure 24A The DCX converter 2401. LLC DCX 2501 is located in the transformer TX. DCXThe primary input terminal 2511 is a full-bridge topology, located at the transformer TX in the LLC DCX 2501. DCX The secondary-side output of the 2512 includes a center-tapped secondary winding and two synchronous rectifiers. Due to the input voltage V of the LLC DCX2501 in Sigma mode... IN,DCX Less than the input voltage V of the LLC DCX 2501 in Delta mode IN,DCX At that time, the transformer TX of LLC DCX2501 DCX The primary side of the transformer in Sigma and Delta modes features a full-bridge topology and a half-bridge topology, respectively. Furthermore, in the LLCDCX 2501, the transformer located at TX... DCX The secondary-side output terminal 2512 can also be modified to include a single secondary-side winding and a full-bridge rectifier. Figure 25 In this embodiment, a two-stage isolated bidirectional buck / boost converter 2502 is implemented. Figure 24A The isolated auxiliary DC / DC converter 2402. The first stage structure 2522 of the isolated bidirectional buck / boost converter 2502 is a non-isolated bidirectional buck / boost converter, which includes an inductor L. BB The buck / boost switches Q5 and Q6, and the mode selection switches Q7 and Q8. When operating in Sigma mode, switch Q8 is on, and inductor L... BB Switches Q5 and Q6 operate as a boost converter. When operating in Delta mode, switch Q7 is turned on, and inductor L... BB Switches Q5 and Q6 operate as a buck converter. The second stage structure 2521 of the isolated bidirectional buck / boost converter 2502 is a bidirectional DC / DC (DCX) converter, which includes a primary-side full-bridge topology Q9-Q6. 12 TX AUX The center-tapped secondary winding and two synchronous rectifiers. When operating in Sigma mode, switch Q9-Q 12 With a 50% duty cycle, the voltage V BB It is converted to a square wave bipolar voltage; while when operating in Delta mode, switch Q9-Q 12 It operates as a synchronous rectifier. Note that the transformer TX in the DCX converter... AUX The secondary side can also be modified to include a single primary winding and a full-bridge rectifier.

[0242] Figure 26 This illustrates an embodiment of the invention. Figure 24A The second example circuit 2600 of the Sigma-Delta converter 2400. Figure 26 In this implementation, LLC DCX 2601 is used. Figure 24AThe DCX converter 2401, wherein the LLC DCX 2601 has an input terminal 2611 and an output terminal 2612, and is substantially the same as... Figure 25 The LLC DCX 2501 is the same. Furthermore, it is... Figure 26 In this implementation, an isolated bidirectional assisted DC / DC flyback converter 2602 based on the Sigma-Delta converter 2600 is used. Figure 24A The auxiliary DC / DC converter 2402. When operating in Sigma mode, switch Q7 is on, and a portion of the load power flows from the voltage source side through the transformer TX of flyback converter 2602. FLY secondary winding N S2F This power is then transmitted to the load. When operating in Delta mode, switch Q6 is on, and a portion of the LLC DCX2601's output power is transmitted via transformer TX. FLY secondary winding N S1F And then transmitted back to the voltage source side.

[0243] Figure 27 This illustrates an embodiment of the invention. Figure 24A The third example circuit 2700 of the Sigma-Delta converter 2400. Figure 27 In this case, it is implemented using LLC DCX 2701. Figure 24A The DCX converter 2401, of which the LLC DCX 2701 is essentially the same as... Figure 26 The LLC DCX 2601 is the same. Furthermore, it is... Figure 27 In this implementation, an isolated flyback converter 2702 is used. Figure 24A The auxiliary DC / DC converter 2402, wherein the isolated flyback converter 2702 is substantially the same as Figure 26 It is the same as the isolated flyback converter 2602, except Figure 27 The synchronous rectifiers SR5, SR6, and SR7 of the flyback converter 2702 are replaced. Figure 26 The diode rectifiers D5, D6, and D7 of the flyback converter 2602.

[0244] At Figure 25 and Figure 26 In the example circuits 2500 and 2600 shown, the input voltage V of the LLC DCX 2501 and 2601 operating in Sigma mode is... IN,DCX Less than the input voltage V of the LLC DCX2501 and 2601 operating in Delta mode IN,DCX Therefore, in Sigma mode, located at transformer TX DCXThe primary side inputs 2511 and 2611 are both full-bridge structures; however, in Delta mode, both inputs 2511 and 2611 can be half-bridge structures. In another embodiment of this invention, when the input voltage of the LLC DCX operating in Sigma and Delta modes is the same, the inputs on the primary side of the transformer in the LLC DCX can be either full-bridge or half-bridge structures. It should be noted that when the power supply voltage V... IN The input voltage V of the LLC DCX is greater than that of the DCX. IN,DCX When the supply voltage V is low, the Sigma-Delta converter operates in Sigma mode; conversely, when the supply voltage V is high, the converter operates in Sigma mode. IN The input voltage V is less than that of LLC DCX. IN,DCX At this time, the Sigma-Delta converter operates in Delta mode. Furthermore, when the Sigma-Delta converter operates in Sigma and Delta modes with different input voltage V values... IN,DCX During operation, there are two maximum efficiency points, located at the minimum supply voltage in Sigma mode and the maximum supply voltage in Delta mode. However, when the Sigma-Delta converter operates at the same V value in both Sigma and Delta modes... IN,DCX During runtime, there exists only one point of maximum efficiency (i.e., at V). IN =V IN,DCX (At times), which is beneficial for certain specific applications.

[0245] Figure 28 This is a block diagram of a Sigma-Delta converter 2800 according to an embodiment of this invention. Unlike... Figure 24A The Sigma-Delta converter 2400 is... Figure 28 The Sigma-Delta converter 2800 includes a non-isolated bidirectional auxiliary DC / DC converter 2802. Figure 29 This illustrates an embodiment of the invention. Figure 28 Example circuit 2900 of the Sigma-Delta converter 2800, wherein the Sigma-Delta converter 2900 includes LLC DCX 2901 and a non-isolated buck-boost converter 2902. For example... Figure 29 As shown, in Sigma mode, switch Q8 is in the ON state; while in Delta mode, switch Q7 is in the ON state.

[0246] Figure 30 This is a block diagram of a Sigma-Delta converter 3000 according to an embodiment of this invention. The Sigma-Delta converter 3000 includes a DCX converter 3001 and an auxiliary DC / DC converter 3002. Unlike... Figure 24AThe Sigma-Delta converter 2400 is... Figure 30 In the Sigma-Delta converter 3000, the load terminal of the bidirectional auxiliary DC / DC converter 3002 is connected to the input terminal 3011 of the DCX converter 3001. Figure 31 , Figure 32 and Figure 33 The embodiments of this case are shown respectively. Figure 30 The first example circuit 3100, the second example circuit 3200, and the third example circuit 3300 of the Sigma-Delta converter 3000 are described. Figure 31 In the example circuit, the LLC DCX3101 and the isolated buck-boost converter 3102 included in the first example circuit 3100 are implemented respectively. Figure 30 The DCX converter 3001 and the auxiliary DC / DC converter 3002. Figure 32 In the example circuit 3200, the LLC DCX 3201 and the isolated flyback converter 3202 are respectively implemented. Figure 30 The DCX converter 3001 and the auxiliary DC / DC converter 3002. Figure 33 In the example circuit 3300, the LLC DCX 3301 and the non-isolated flyback converter 3302 are respectively implemented. Figure 30 DCX converter 3001 and auxiliary DC / DC converter 3002.

[0247] It should be noted that the above are merely preferred embodiments for illustrating this case, and this case is not limited to the described embodiments. The scope of this case is determined by the appended claims. Furthermore, this case can be modified in various ways by those skilled in the art, but all modifications shall not depart from the protection sought by the appended claims.

Claims

1. A converter that receives a power supply voltage from a voltage source and provides an output voltage to a load, and includes: A first DC / DC converter having an input terminal, a first output terminal, and a second output terminal; and A second DC / DC converter has an input terminal and an output terminal, and receives a control signal derived from the output voltage. The two input terminals of the first DC / DC converter and the second DC / DC converter are connected in series between the two ends of the voltage source, so that the voltage at the input terminal of the first DC / DC converter is less than the power supply voltage. The first output terminal of the first DC / DC converter provides the output voltage, and the second output terminal of the first DC / DC converter is connected in parallel with the output terminal of the second DC / DC converter. The second DC / DC converter adjusts the output voltage according to the control signal. The power output from the output terminal of the second DC / DC converter is transmitted to the second output terminal of the first DC / DC converter, and then transmitted to the load via the first output terminal of the first DC / DC converter.

2. The converter of claim 1, wherein the second DC / DC converter comprises a boost converter.

3. The converter of claim 2, wherein the boost converter is non-isolated.

4. The converter of claim 2, wherein the first DC / DC converter is isolated by a transformer.

5. The converter of claim 1, wherein the first DC / DC converter comprises an LLC resonant converter.

6. The converter of claim 1, wherein the first DC / DC converter further comprises a plurality of switches forming a full-bridge structure.

7. A converter that receives a power supply voltage from a voltage source and provides an output voltage to a load, and includes: A first DC / DC converter has an input terminal and an output terminal, wherein the input terminal receives the power supply voltage from the voltage source; and A second DC / DC converter has an input terminal and an output terminal, and receives a control signal derived from the output voltage. The two output terminals of the first DC / DC converter and the second DC / DC converter are connected in series to provide the output voltage to the load, so that the voltage at the output terminal of the first DC / DC converter is less than the output voltage, and the second DC / DC converter adjusts the output voltage according to the control signal.

8. The converter of claim 7, wherein the two input terminals of the first DC / DC converter and the second DC / DC converter are connected in parallel, and each input terminal receives the power supply voltage.

9. The converter of claim 8, wherein the second DC / DC converter includes a flyback converter.

10. The converter of claim 7, wherein the input terminal of the second DC / DC converter is connected in parallel with the output terminal of the first DC / DC converter.

11. The converter of claim 10, wherein the second DC / DC converter comprises a buck-boost converter.

12. The converter of claim 7, wherein the first DC / DC converter further includes a second output terminal, and the input terminal of the second DC / DC converter is connected in parallel with the second output terminal of the first DC / DC converter.

13. The converter of claim 12, wherein the first DC / DC converter includes an isolation transformer.

14. The converter of claim 12, wherein the second DC / DC converter comprises a buck converter.

15. The converter of claim 14, wherein the buck converter is non-isolated.

16. The converter of claim 7, further comprising a second voltage source, wherein the input terminal of the second DC / DC converter is connected to the second voltage source.

17. The converter of claim 16, wherein the first DC / DC converter comprises an isolated DC / DC converter.

18. The converter of claim 7, wherein the first DC / DC converter comprises an LLC resonant converter.

19. The converter of claim 7, wherein the first DC / DC converter further comprises a plurality of switches forming a full-bridge structure.

20. The converter of claim 7, wherein the first DC / DC converter further comprises an isolation transformer.

21. A converter that receives a power supply voltage from a voltage source and provides an output voltage to a load, and includes: A first DC / DC converter having an input terminal and an output terminal, wherein the output terminal is connected to the load; and A second DC / DC converter has an input terminal and an output terminal, and receives a control signal derived from the output voltage. The input terminal of the first DC / DC converter and the output terminal of the second DC / DC converter are connected in series between the two ends of the voltage source, so that the voltage at the input terminal of the first DC / DC converter is greater than the power supply voltage. The second DC / DC converter adjusts the output voltage according to the control signal. The voltage source and the first DC / DC converter have a common reference ground voltage.

22. The converter of claim 21, wherein the first DC / DC converter comprises an LLC resonant converter.

23. The converter of claim 21, wherein the input terminal of the first DC / DC converter further includes a plurality of switches forming a full-bridge structure.

24. The converter of claim 21, wherein the first DC / DC converter includes an isolation transformer.

25. The converter of claim 21, wherein the second DC / DC converter comprises a buck-boost converter.

26. The converter of claim 25, wherein the buck-boost converter is non-isolated.

27. The converter of claim 21, wherein the first DC / DC converter further includes a second output terminal, the second output terminal of the first DC / DC converter being connected in parallel with the input terminal of the second DC / DC converter.

28. The converter of claim 21, wherein the input terminal of the second DC / DC converter is connected to the voltage source.

29. The converter of claim 21, wherein the two input terminals of the first DC / DC converter and the second DC / DC converter are connected in parallel.

30. The converter of claim 29, wherein the second DC / DC converter comprises a buck converter.

31. The converter of claim 30, wherein the second DC / DC converter includes a flyback converter.

32. The converter of claim 31, wherein the second DC / DC converter is non-isolated.

33. The converter of claim 21, wherein the input terminal of the second DC / DC converter is connected to a second voltage source.

34. The converter of claim 33, wherein the second DC / DC converter is non-isolated.

35. A converter that receives a power supply voltage from a voltage source and provides an output voltage to a load, and includes: A first DC / DC converter having an input terminal and an output terminal; and A second DC / DC converter has a first input / output terminal and a second input / output terminal, wherein the second DC / DC converter is bidirectional and receives a control signal derived from the output voltage. The input terminal of the first DC / DC converter and the first input / output terminal of the second DC / DC converter are connected in series between the two ends of the voltage source, and the second DC / DC converter adjusts the output voltage according to the control signal.

36. The converter of claim 35, wherein the first DC / DC converter comprises an LLC resonant converter.

37. The converter of claim 35, wherein the first DC / DC converter further comprises a plurality of switches forming a full-bridge structure.

38. The converter of claim 35, wherein the first DC / DC converter includes an isolation transformer.

39. The converter of claim 35, wherein the second DC / DC converter further comprises one or more switches that enable the converter to operate at a voltage at the input terminal of the first DC / DC converter that is less than or greater than the power supply voltage.

40. The converter of claim 35, wherein the second input / output terminal of the second DC / DC converter is connected to the load.

41. The converter of claim 40, wherein the second DC / DC converter comprises a buck-boost converter.

42. The converter of claim 40, wherein the second DC / DC converter comprises a flyback converter.

43. The converter of claim 40, wherein the second DC / DC converter includes an isolation transformer.

44. The converter of claim 43, wherein the second input / output terminal includes a center tap winding, a plurality of switches and a plurality of diodes or synchronous rectifiers, the plurality of switches and the plurality of diodes or synchronous rectifiers forming a full-bridge structure.

45. The converter of claim 35, wherein the first DC / DC converter further includes a second output terminal, the second output terminal of the first DC / DC converter being connected in parallel with the second input / output terminal of the second DC / DC converter.

46. ​​The converter of claim 45, wherein the second DC / DC converter comprises a buck-boost converter.

47. The converter of claim 46, wherein the second input / output terminal includes a plurality of switches forming a full-bridge structure.

48. The converter of claim 35, wherein the input terminal of the first DC / DC converter is connected in parallel with the second input / output terminal of the second DC / DC converter.

49. The converter of claim 48, wherein the second DC / DC converter includes an isolation transformer.

50. The converter of claim 48, wherein the second DC / DC converter comprises a buck-boost converter.

51. The converter of claim 48, wherein the second DC / DC converter includes a flyback converter.

52. The converter of claim 51, wherein the second input / output terminal includes a center tap winding, a plurality of switches and a plurality of diodes or synchronous rectifiers, the plurality of switches and the plurality of diodes or synchronous rectifiers forming a full-bridge structure.

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