A driving charge recycling device for a single-inductor multiple-output power supply

Abstract

The present invention discloses a driving charge recovery device for a single-inductor multiple-output power supply. The driving charge recovery device includes a voltage acquisition unit, a plurality of switching devices, and a controller. The plurality of switching devices are respectively used to be connected between the line of the voltage V output by the P-type buffer and the ground VSS and the output ends of each output transistor, and between the line of the voltage V output by the N-type buffer and the output ends of some output transistors. The controller makes a comprehensive judgment according to the voltage and power, controls the switching devices to work, and thus preferentially discharges charges. The present invention can recover the driving charges of the pull-up transistor to a higher load level to obtain a higher recovery power, and recover the driving charges of the output transistor to a lower load level, and there will be no problem of the body diode conducting; the structure is simple and can be applied to small-volume and low-cost consumer electronics and vehicle-mounted electronics. PBUF of the output of the P-type buffer and the ground VSS and the output ends of each output transistor, and between the line of the voltage V output by the N-type buffer and the output ends of some output transistors. The controller makes a comprehensive judgment according to the voltage and power, controls the switching devices to work, and thus preferentially discharges charges. The present invention can recover the driving charges of the pull-up transistor to a higher load level to obtain a higher recovery power, and recover the driving charges of the output transistor to a lower load level, and there will be no problem of the body diode conducting; the structure is simple and can be applied to small-volume and low-cost consumer electronics and vehicle-mounted electronics. NBUF The present invention can recover the driving charges of the pull-up transistor to a higher load level to obtain a higher recovery power, and recover the driving charges of the output transistor to a lower load level, and there will be no problem of the body diode conducting; the structure is simple and can be applied to small-volume and low-cost consumer electronics and vehicle-mounted electronics.

Description

Technical Field

[0001] The present invention relates to the technical field of power converters, and particularly relates to a driving charge recovery device for a single-inductor multiple-output power supply. Background Art

[0002] As Figure 1 shown, single-inductor multiple-output (SIMO) DC-DC converters are becoming increasingly popular in consumer electronics applications. Compared with traditional single-output BUCK or BOOST power supplies, SIMO technology can achieve a smaller area and can greatly reduce the material cost. Due to these advantages, SIMO technology will gradually replace traditional BUCK technology in the field of consumer electronics.

[0003] To improve the conversion efficiency of SIMO power supplies, the losses during energy transmission should be reduced. The energy losses mainly include conduction loss and switching loss, where the switching loss mainly comes from the periodic charging and discharging of the power transistor driver. Charge recovery technology can reduce the switching loss, and its significance lies in recycling the discharge current back to the output load instead of wasting it to ground, thereby optimizing the power supply efficiency.

[0004] In a SIMO power supply, when the currents and voltages of multiple loads change due to customer requirements, it is still necessary to effectively perform charge recovery without affecting the normal operation of the system. Summary of the Invention

[0005] The object of the present invention is to provide a driving charge recovery device for a single-inductor multiple-output power supply in view of the deficiencies of the prior art.

[0006] To achieve the above object, the present invention provides a driving charge recovery device for a single-inductor multiple-output power supply. The single-inductor multiple-output power supply includes a pull-up transistor S HS , a pull-down transistor S LS and multiple output transistors. The pull-up transistor S HS , the pull-down transistor S LS and the multiple output transistors are respectively connected to a driver. The driver connected to the pull-up transistor S HS is controlled by the voltage output by a P-type buffer, and several output transistors are controlled by the voltage output by an N-type buffer. The voltages output by the output transistors are different. The driving charge recovery device includes:

[0007] A voltage acquisition unit for collecting the voltage V PBUF output by the P-type buffer and the voltage VNBUF , and the voltage controlled by the output tube for output;

[0008] A controller for judging the output power of each output tube and setting the charge recovery voltage judgment priority of the driver of the pull-up tube S HS as the output voltages of the output tubes sorted from high to low, ground VSS, and the charge recovery judgment priority of the driver of the output tube as the output voltages of some output tubes sorted from low to high, ground VSS;

[0009] A plurality of switching devices for respectively connecting the voltage V output by the P-type buffer PBUF between the line and ground VSS and the output terminals of each output tube, and connecting the voltage V output by the N-type buffer NBUF between the line and the output terminals of some output tubes;

[0010] The controller is further configured to sequentially judge the magnitude relationship between the voltage V output by the P-type buffer PBUF and the voltage V output by the N-type buffer NBUF and the output voltage of the output tube. If the voltage V output by the P-type buffer PBUF and / or the voltage V output by the N-type buffer NBUF is greater than the output voltage of a certain output tube, it is further judged whether the output power of the output tube controlling the output of this voltage is above the set power threshold. If it is above the set power threshold, the corresponding switching device is controlled to close to connect the voltage V output by the P-type buffer PBUF and / or the voltage V output by the N-type buffer NBUF to this load. Otherwise, the switching device between the line of the voltage V output by the P-type buffer PBUF and / or the line of the voltage V output by the N-type buffer NBUF and ground VSS is controlled to close to connect the voltage V output by the P-type buffer PBUF and the voltage V output by the N-type buffer NBUF to ground VSS.

[0011] Further, the output tube includes a first output tube S O1p8 , a second output tube S OL1 and a third output tube S OL2 . The voltages controlled by the first output tube S O1p8 , the second output tube S OL1 and the third output tube S OL1 for output are V O1p8 , V OL1 and V OL2 , and V O1p8 > V OL1 , VOL2 。

[0012] Further, the pull-down tube S LS and the first output tube S O1p8 are connected to a driver that operates in the V O1p8 -0 domain.

[0013] Further, the switching device is a MOS transistor.

[0014] Beneficial effects: The present invention can simultaneously recover the driving charges of the pull-up tube and the output tubes of a single-inductor multi-output power supply, and can automatically select the optimal output channel for charge discharge. The driving charge of the pull-up tube is recovered to a higher load level to obtain higher recovery power, and the driving charge of the output tubes is recovered to a lower load level, without the problem of body diode conduction; the structure is simple and can be applied to small-sized, low-cost consumer electronics and automotive electronics. Description of the Drawings

[0015] Figure 1 is a schematic diagram of the principle of a single-inductor multi-output power supply in the prior art;

[0016] Figure 2 is a schematic diagram of the recovery principle of the driving charge of the pull-up tube of the single-inductor multi-output power supply according to an embodiment of the present invention;

[0017] Figure 3 is a schematic diagram of the recovery principle of the driving charge of the output tubes of the single-inductor multi-output power supply according to an embodiment of the present invention;

[0018] Figure 4 is a schematic diagram of the driving charge recovery process of the pull-up tube according to an embodiment of the present invention;

[0019] Figure 5 is a schematic diagram of the driving charge recovery process of the output tubes according to an embodiment of the present invention;

[0020] Figure 6 is a schematic diagram of the controller according to an embodiment of the present invention. Detailed Embodiments

[0021] The present invention will be further clarified below in conjunction with the drawings and specific embodiments. These embodiments are implemented on the premise of the technical solution of the present invention, and it should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention.

[0022] As Figure 2 and Figure 3 shown, an embodiment of the present invention provides a driving charge recovery device for a single-inductor multi-output power supply, wherein the above single-inductor multi-output power supply includes a pull-up tube S HS , a pull-down tube S LS and a plurality of output tubes, the pull-up tube SHS and the pull-down tube S LS and multiple output tubes are respectively connected to a driver. For details, please refer to Figure 2 and Figure 3 , the pull-up tube S HS and the pull-down tube S LS and the driver connected to the gates of multiple output tubes is the driver. The driver connected to the pull-up tube S HS is controlled by the voltage output by a P-type buffer (P-Buffer). Specifically, its driver operates in the VBat-VPBUF domain. A number of output tubes are controlled by the voltage output by an N-type buffer. The voltages output by the output tubes are different. The relevant voltage regulating components are omitted in the figure.

[0023] The driving charge recovery device according to the embodiment of the present invention includes a voltage acquisition unit, a controller, and multiple switching devices. Among them, the switching devices preferably use MOS tubes. The voltage acquisition unit is used to collect the voltage V PBUF output by the P-type buffer, the voltage V NBUF output by the N-type buffer, and the voltage output by the output tubes. The voltage information acquired by the voltage acquisition unit is sent to the controller. The controller is used to judge the output power of each output tube and set the charge recovery voltage judgment priority of the driver of the pull-up tube S HS as the output voltages of the output tubes are sorted from high to low, ground VSS, and the charge recovery judgment priority of the driver of the output tube is that the output voltages of some output tubes are sorted from low to high, ground VSS. The multiple switching devices are respectively used to connect between the line of the voltage V PBUF output by the P-type buffer and ground VSS and the output terminals of each output tube, and between the line of the voltage V NBUF output by the N-type buffer and the output terminals of some output tubes.

[0024] The controller is further used to sequentially judge the magnitude relationship between the voltage V PBUF output by the P-type buffer and the voltage V NBUF output by the N-type buffer and the output voltage of the output tube according to the voltage judgment priority. If the voltage V PBUF output by the P-type buffer and / or the voltage V NBUF output by the N-type buffer is greater than the output voltage of a certain output tube, it is further judged whether the output power of the output tube controlling the output of this voltage is above the set power threshold. If it is above the set power threshold, the corresponding switching device is controlled to close to connect the line of the voltage V PBUF output by the P-type buffer and / or the voltage V NBUF output by the N-type buffer to this load. Otherwise, the line connected to the voltage V PBUF output by the P-type buffer and / or the line of the voltage V NBUFThe switching device between the line and ground VSS is closed to connect the voltage V output by the P-type buffer PBUF and the voltage V output by the N-type buffer NBUF of the line to ground VSS.

[0025] The output transistors of the embodiments of the present invention include a first output transistor S O1p8 , a second output transistor S OL1 and a third output transistor S OL2 . The voltages controlled by the first output transistor S O1p8 , the second output transistor S OL1 and the third output transistor S OL1 for output are V O1p8 , V OL1 and V OL2 respectively, and V O1p8 > V OL1 , V OL2 . Correspondingly, the priority of the charge recovery voltage judgment of the driver of the pull-up transistor S HS is that the output voltages of the output transistors from high to low are: V O1p8 > Max(V OL1 , V OL2 ) > Min(V OL1 , V OL2 ) > ground VSS.

[0026] See Figure 4 . When judging the charge recovery of the driver of the pull-up transistor S HS , first judge whether V PBUF is greater than V O1p8 . If so, then judge whether the power of the load connected to V O1p8 is above the set threshold. If the power of the load connected to V O1p8 is above the set threshold, it is considered that the output loop of V O1p8 has not entered the light load state, and the energy can be recovered to the output loop of V O1p8 , and the corresponding switching device can be controlled to close. If the power of the load connected to V O1p8 is lower than the set threshold, it is considered that the output loop of V O1p8 has entered the light load state, and the driving charge cannot be recovered to this output loop. At this time, find the higher level and non-light load output among V OL1 and V OL1 . If all three output loops enter the light load state, the energy is discharged to ground VSS to avoid the output level from floating up.

[0027] The pull-down transistor S LS of the embodiments of the present invention and the driver connected to the first output transistor S O1p8 operate in the V O1p8 -0 domain, that is, the pull-down transistor SLS and the first output transistor S O1p8 is directly supplied by V O1p8 . For the input side, this can eliminate the design of an N-Buffer, and the efficiency is also higher. Refer to Figure 3 and Figure 5 . In the embodiments of the present invention, only the charge of the drivers of the second output transistor S OL1 and the third output transistor S OL2 is recycled. V OL1、 V OL2 is driven by the V NBUF potential (generated by the N-Buffer), and its discharge current can be discharged to either V OL1、 V OL2 or ground VSS. Additionally, the discharge current here must be discharged to the output loop with a lower potential in V OL1、 V OL2 , otherwise it may cause the output transistor to not be fully turned off. During the recycling judgment, first judge whether V OL1 is less than V OL2 . If so, then judge whether the V OL1 output loop enters the light load. If the V OL1 output loop does not enter the light load, the energy can be recycled to the V OL1 output loop; otherwise, judge whether the V OL2 output loop enters the light load. If the V OL2 output loop does not enter the light load, the energy can be recycled to the V OL2 output loop, otherwise, discharge the energy to ground VSS.

[0028] Specifically, refer to Figure 6 . The controller in the embodiments of the present invention includes two comparators, three light load detectors, and a decision maker. The two comparators are comparator C1 and comparator C2 respectively. Comparator C1 is used to receive the two voltage signals of V PBUF and V O1p8 , and output the signal Vpbuf_high according to the magnitude relationship between V PBUF and V O1p8 . Comparator C2 is used to receive the two voltage signals of V OL1 and V OL2 , and output the signal Vpbuf_high according to the magnitude relationship between V OL1 and V OL2Based on the magnitude relationship, the output signal Vol2_low is output. The three light load detectors are Light Load Detector 1, Light Load Detector 2, and Light Load Detector 3, and their inputs are the load currents output by the three output tubes respectively. Light Load Detector 1, Light Load Detector 2, and Light Load Detector 3 respectively determine whether they enter the light load state based on the load current, and then output the signals LL_O1P8, LL_OL1, and LL_OL2. The above output signals Vpbuf_high, Vol2_low, LL_O1P8, LL_OL1, and LL_OL2 will all enter the decision maker as inputs, and the decision maker will output signals PBUF_sel<1:0>, VSSH_OL1_sel<1:0>, and VSSH_OL2_sel<1:0> to control the operation of the switching device.

[0029] The above description is only the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art of this technology, the other parts not specifically described belong to the prior art or common general knowledge. Without departing from the principle of the present invention, several improvements and refinements can still be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A driving charge recycling device for a single-inductor multiple-output power supply, the single-inductor multiple-output power supply including a pull-up transistor S HS , a pull-down transistor S LS and a plurality of output transistors, the pull-up transistor S HS , the pull-down transistor S LS and the plurality of output transistors are respectively connected to a driver, the driver connected to the pull-up transistor S HS is controlled by the voltage output by a P-type buffer, and several output transistors are controlled by the voltage output by an N-type buffer, and the voltages output by the output transistors are different, and it is characterized in that The driving charge recovery device includes: A voltage acquisition unit for collecting the voltage V output by the P-type buffer PBUF and the voltage V output by the N-type buffer NBUF , and the voltage output by the output transistor control A controller is used to determine the output power of each output transistor and set the charge recovery voltage determination priority of the driver of the pull-up transistor S HS as the output voltages of the output transistors are sorted from high to low, ground VSS, and the charge recovery determination priority of the driver of the output transistors is that the output voltages of some output transistors are sorted from low to high, ground VSS; A plurality of switching devices, respectively connected between the line of the voltage V output by the P-type buffer and the ground VSS and the output terminals of each output transistor, and between the line of the voltage V output by the N-type buffer and the output terminals of some output transistors; PBUF NBUF ​​ The controller is further configured to respectively determine the magnitudes of the voltage V PBUF output by the P-type buffer and the voltage V NBUF output by the N-type buffer with respect to the output voltage of the output transistor. If the voltage V PBUF output by the P-type buffer and / or the voltage V NBUF output by the N-type buffer is greater than the output voltage of a certain output transistor, it further determines whether the output power of the output transistor controlling the output of this voltage is above the set power threshold. If it is above the set power threshold, it controls the corresponding switching device to close to connect the line of the voltage V PBUF output by the P-type buffer and / or the voltage V NBUF output by the N-type buffer to the load. Otherwise, it controls the switching device between the line of the voltage V PBUF output by the P-type buffer and / or the voltage V NBUF output by the N-type buffer and the ground VSS to close, to connect the line of the voltage V PBUF output by the P-type buffer and / or the voltage V NBUF output by the N-type buffer to the ground VSS.

2. The driving charge recycling device for a single-inductor multi-output power supply according to claim 1, wherein The output tube includes a first output tube S O1p8 , a second output tube S OL1 and a third output tube S OL2 . The voltages controlled by the first output tube S O1p8 , the second output tube S OL1 and the third output tube S OL1 are V O1p8 , V OL1 and V OL2 respectively, and V O1p8 > V OL1 , V OL2 .

3. The driving charge recycling device for a single-inductor multi-output power supply according to claim 2, wherein The pull-down tube S LS and the driver connected to the first output tube S O1p8 operates in the V O1p8 -0 domain.

4. A driving charge recovery device for a single-inductor multi-output power supply according to claim 1, characterized in that, The switching device is a MOS transistor.

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