Load current detection circuit and method

Abstract

The embodiment of the invention provides a load current detection circuit and method, the load current detection circuit is connected with a voltage stabilizing circuit core, the voltage stabilizing circuit core comprises a power module and a load which are connected, the load current detection circuit comprises a current sampling module, a comparison module, a control module and a programmable current source, the input end of the current sampling module is connected with a power module in the voltage stabilizing circuit core, and the output end is connected with the programmable current source; the comparison module is used for comparing the first node voltage with the second node voltage to generate high and low levels and outputting the high and low levels to the control module; the input end of the control module is connected with the output end of the comparison module; and the input end of the programmable current source is connected with the output end of the control module.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of integrated power supplies, and more specifically, to a load current detection circuit and method. Background Art

[0002] Integrated power supplies are typically integrated into processors to power them. To provide a more stable power supply voltage, it is often necessary to detect the load current and predict the load current magnitude at the next moment based on multiple detection results before the current moment. Because processors for their application are typically manufactured using advanced semiconductor manufacturing processes, the load current detection circuit needs to be small in area to reduce costs. Furthermore, due to the lower voltages of advanced semiconductor manufacturing processes, the load current detection circuit must be able to operate at low power supply voltages (e.g., 0.6V).

[0003] In the related art, the load current detection circuit adopts an open-loop detection method, which is usually composed of a current sampling module, an off-chip high-precision resistor, and an analog-to-digital converter. The disadvantages include: the need for a multi-bit high-precision analog-to-digital converter to complete the conversion between the sampled voltage and the digital signal corresponding to the load current, which has a large circuit area and does not meet the processor's requirement for a small average load current detection circuit area; the need to connect a high-precision resistor outside the chip to complete the conversion from the sampled current to the sampled voltage, which will reduce the integration of the processor chip; in order to achieve accurate current replication of the power module by the current sampling module, a voltage clamping module (operational amplifier) ​​is required to clamp the drain of the transistor in the power module and the drain of the transistor in the current sampling module. However, the design of the operational amplifier at a low power supply voltage (0.6V) faces great challenges. The above disadvantages make the application of the existing technology for average load current detection in processors very limited. Summary of the Invention

[0004] The embodiments of the present application provide a load current detection circuit and method to at least solve the problems in the related art that the load current detection circuit adopts an open-loop detection method, needs to copy the load current and then apply the copied current to an external high-precision resistor to generate a sampling voltage, and finally process the sampling voltage into a digital signal corresponding to the load current through an analog-to-digital converter. The detection circuit area is large, the device requirements are high, and the circuit design is difficult to implement.

[0005] According to one embodiment of the present application, a load current detection circuit is provided, which is connected to a voltage stabilization circuit core. The voltage stabilization circuit core includes a connected power module and a load. The load current detection circuit includes: a current sampling module, a comparison module, a control module and a programmable current source, wherein the current sampling module has an input end connected to the power module in the voltage stabilization circuit core and an output end connected to the programmable current source, and is used to perform a K:1 ratio copy of the current of the power module to provide current to the programmable current source, wherein K is a positive integer; the comparison module is used to compare the first node voltage and the second node voltage to generate a high and low level, and output it to the control module. a control module, wherein the first node voltage is the voltage of the connection node between the power module and the load, and the second node voltage is the voltage of the connection node between the current sampling module and the programmable current source; a control module, whose input end is connected to the output end of the comparison module, and is used to adjust the size of the output signal according to the high and low levels output by the comparison module, and output the output signal to the programmable current source; a programmable current source, whose input end is connected to the output end of the control module, and is used to adjust the current value of the programmable current source according to the output signal until the output signal stabilizes within a preset range, so that the absolute value of the difference between the current value and 1 / K of the load current value is less than a preset threshold.

[0006] According to another embodiment of the present application, a load current detection method is provided, which is applied to the above-mentioned load current detection circuit, including: a comparison module compares a first node voltage and a second node voltage and outputs a high and low level, wherein the first node voltage is the voltage of the connection node between the power module and the load, and the second node voltage is the voltage of the connection node between the current sampling module and the programmable current source that performs a K:1 replication of the current of the power module; a control module instructs the programmable current source to adjust the current value through an output signal according to the high and low levels until the output signal stabilizes within a preset range, so that the absolute value of the difference between the current value and 1 / K of the load current value is less than a preset threshold, wherein K is a positive integer.

[0007] Through this application, since the comparison module compares the load voltage and the programmable current source voltage and outputs the comparison result to the control module in the form of high and low levels, the control module also adjusts the output signal to the programmable current source based on the received high and low levels, thereby controlling the current value of the programmable current source. Based on the current sampling module replicating the current of the power module in a K:1 ratio, after the closed-loop circuit, when the output signal is in a stable state, the current value of the programmable current source approaches 1 / K of the load current value, that is, the load current value is obtained by the current value of the programmable current source. Therefore, it can solve the problems of the load current detection circuit in the related art that uses an open-loop detection method, requires that the copied current be applied to an external high-precision resistor to generate a sampling voltage after replicating the load current, and finally, the sampling voltage is processed into a digital signal corresponding to the load current through an analog-to-digital converter. This leads to a large detection circuit area, high device requirements, and difficult circuit design. The closed-loop negative feedback circuit structure formed by the comparison module, control module, and programmable current source only requires the comparison module and control module to complete the analog-to-digital signal conversion. This reduces hardware resource consumption while meeting the detection bandwidth, achieving a small area and low cost. Furthermore, no high-precision resistors are required to convert the sampled current to the sampled voltage, which can achieve higher chip integration. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 is a structural block diagram of a load current detection circuit according to an embodiment of the present application;

[0009] Figure 2 is a load current detection circuit diagram according to an embodiment of the present application;

[0010] Figure 3 is a load current detection circuit diagram according to yet another embodiment of the present application;

[0011] Figure 4 is a load current detection circuit diagram according to another embodiment of the present application;

[0012] Figure 5 is a load current detection circuit diagram according to another embodiment of the present application;

[0013] Figure 6 is a schematic diagram of a load current detection process according to an embodiment of the present application;

[0014] Figure 7 4 is a flow chart of a load current detection method according to an embodiment of the present application. DETAILED DESCRIPTION

[0015] The embodiments of the present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0016] In related technologies, load current detection circuits employ an open-loop approach, typically consisting of a current sampling module, an off-chip high-precision resistor, and an analog-to-digital converter. The current sampling module first replicates the power module's current. This current is then applied to the resistor, converting the sampled current into a sampled voltage. Finally, the analog-to-digital converter processes the sampled voltage into a digital signal corresponding to the load current, completing load current detection.

[0017] During detection, the current of the power module is first copied through the current sampling module, and then the sampled current is converted into a sampling voltage by applying the current to the resistor. Finally, the sampling voltage is processed into a digital signal corresponding to the load current through the analog-to-digital converter, thereby completing the load current detection.

[0018] In this embodiment, a load current detection circuit is provided. Figure 1 is a structural block diagram of a load current detection circuit according to an embodiment of the present application, such as Figure 1 As shown, the load current detection circuit is connected to the voltage stabilization circuit core, which includes a power module and a load connected thereto. The load current detection circuit includes: a current sampling module, a comparison module, a control module, and a programmable current source. The current sampling module has an input end connected to the power module in the voltage stabilization circuit core and an output end connected to the programmable current source, and is used to replicate the current of the power module in a K:1 ratio to provide current to the programmable current source, where K is a positive integer. The comparison module is used to compare a first node voltage with a second node voltage to generate a high and low level, and output it to the control module, where the first node voltage is the voltage of the connection node between the power module and the load, and the second node voltage is the voltage of the connection node between the current sampling module and the programmable current source. The control module has an input end connected to the output end of the comparison module, and is used to adjust the magnitude of the output signal according to the high and low levels output by the comparison module, and output the output signal to the programmable current source. The programmable current source has an input end connected to the output end of the control module, and is used to adjust the current value of the programmable current source according to the output signal until the output signal stabilizes within a preset range, so that the absolute value of the difference between the current value and 1 / K of the load current value is less than a preset threshold.

[0019] In an exemplary embodiment, the power module in the load current detection circuit is a single or cascaded MOS power tube.

[0020] In one embodiment, Figure 2As shown, the power module in the load current detection circuit is a single MOS power transistor M1, whose source terminal is connected to the power supply Vin, the gate terminal is controlled by the control signal Vctrl, and the drain terminal is connected to the load to provide current to the load. M1 can also be replaced with a cascaded MOS power transistor, which is not limited in this embodiment of the application.

[0021] like Figure 2 As shown, the load is a processor module, which is represented by a current source Iload and includes a decoupling capacitor C1 to reduce the ripple of the output voltage Vout.

[0022] In an exemplary embodiment, the current sampling module in the load current detection circuit is a MOS power tube of the same type as the power module and a single or cascade structure with a size in a K:1 ratio.

[0023] In one embodiment, Figure 2 As shown, the current sampling module uses a single MOS power tube M2 of the same type as the power module but with a size in a K:1 ratio. Its source terminal is connected to the power supply Vin, and the gate terminal is connected to the gate terminal of the power tube. It is also controlled by the control signal Vctrl to replicate the power tube current in a K:1 ratio. The drain terminal is connected to the programmable current source to provide current to the programmable current source. In addition to using a single MOS detection tube, a MOS detection tube with a cascode (common source and common gate) structure of the same type as the power tube can also be used. This embodiment of the application does not limit this.

[0024] In an exemplary embodiment, the load current detection circuit further includes: a first filtering module connected to the comparison module, for performing low-pass filtering on the first node voltage; and a second filtering module connected to the comparison module, for performing low-pass filtering on the second node voltage.

[0025] In one embodiment, Figure 2 As shown, a first-order RC low-pass filter is formed by a series resistor R2 and a parallel capacitor C4, which is equivalent to a first filtering module and filters the output voltage Vout. Another first-order RC low-pass filter is formed by a series resistor R1 and a parallel capacitor C3, which is equivalent to a second filtering module and filters the detection voltage Vsense. It should be noted that in the embodiment of the present application, the output voltage Vout corresponds to the first node voltage, and the detection voltage Vsense corresponds to the second node voltage. In addition to using a first-order RC low-pass filter, a second-order or high-order RC low-pass filter can also be used, and a digital filter can also be used.

[0026] In an exemplary embodiment, the comparison module in the load current detection circuit includes: a first chopping circuit, a second chopping circuit and a comparator, wherein the first chopping circuit has an input end connected to the first filtering module and the second filtering module, and an output end connected to the input end of the comparator, and is used to swap the two input ends of the comparator in each clock cycle; the second chopping circuit has an input end connected to the output end of the comparator, and an output end connected to the control module, and is used to swap the two output ends of the comparator in each clock cycle; the comparator has an output end connected to the control module, and is used to compare the voltage passing through the first filtering module and the first chopping circuit with the voltage passing through the second filtering module and the first chopping circuit.

[0027] In one embodiment, Figure 2 As shown, the comparison module consists of a clock-controlled dynamic comparator and a first chopping circuit and a second chopping circuit. The voltage nodes of Vsense and Vout after passing through the filter are connected to the positive input terminal Vip and the negative input terminal Vin of the comparator respectively through the chopping circuit, and the comparator compares the two voltages. When the positive input terminal voltage Vip is greater than the negative input terminal voltage Vin, a high level is output; when the positive input terminal voltage Vip is less than the negative input terminal voltage Vin, a low level is output. The chopping circuit swaps the two input terminals of the comparator in each clock cycle, so that the comparator input offset voltage is positive in some clock cycles and negative in some clock cycles. After averaging, the influence of the comparator input offset voltage on the load current detection accuracy can be reduced. In addition to using a clock-controlled comparator, a static comparator can also be used. In addition to using a chopping circuit, in order to improve the input voltage comparison accuracy of the comparator, a self-zeroing pre-amplifier with a ping-pong structure can also be added to the comparator input. In addition to using the cmp_clk of the comparator Figure 2 The single-phase clock in the control circuit is a single detection circuit, cmp_clk can be used as follows Figure 3 The multi-phase clock shown controls multiple detection circuits and then averages the multiple detection results.

[0028] In one embodiment, Figure 2As shown, the control module adopts successive approximation register (SAR) logic control, and its input is connected to the comparator output, and its logic output signal is adjusted according to the high and low levels of the comparator output. Its logic output signal controls the size of the programmable current source. When the comparator outputs a low level, its logic output signal D<7:0> is reduced, that is, the current value of the programmable current source is reduced; when the comparator outputs a high level, its logic output signal D<7:0> is increased, that is, the current value of the programmable current source is increased. After a search, the SAR control logic outputs the final D<7:0>, that is, OUT<7:0>. The bit width of the control signal output by the control module is not limited to 8 bits, and can be adjusted according to the detection accuracy. In addition to using successive approximation register (SAR) logic control, the control module can also use Figure 4 The binary code control logic based on bidirectional counter control shown in the figure can also be used as Figure 5 The thermometer code control logic based on bidirectional shift register control is shown.

[0029] In one embodiment, Figure 2 As shown, the programmable current source adopts a current mirror structure to copy the reference current. The current size is controlled by the successive approximation register (SAR) logic output signal, and the adjustable current of the programmable current source is divided into binary. It also includes a decoupling capacitor C2 to reduce the ripple of the detection voltage Vsense. When the current value of the programmable current source is greater than 1 / K of the load current, the drain voltage Vsense of the detection tube is less than the drain voltage Vout of the power tube; when the current value of the programmable current source is less than 1 / K of the load current, the drain voltage Vsense of the detection tube is greater than the drain voltage Vout of the power tube. In addition to the binary division method for the adjustable current of the programmable current source, when the control logic adopts the thermometer code system, the current of the programmable current source adopts a proportional division method. The number of current levels that the programmable current source can adjust is not limited to 8, and can be adjusted according to the detection accuracy.

[0030] In an exemplary embodiment, the load current detection circuit further includes: an algorithm module connected to the control module, configured to perform averaging processing on an output signal output by the control module within a preset time period.

[0031] In one embodiment, the algorithm module uses a sliding average algorithm to average the OUT<7:0> output by the SAR control logic within a certain period of time, and then outputs OUT_AVG<7:0> to the upper control module for processor power consumption prediction. Figure 6As shown, Iref (the current value of the programmable current source) changes with time and eventually approaches Iload / K (the load current value).

[0032] In this embodiment, a load current detection method is also provided. Figure 7 As shown, the method includes the following steps:

[0033] In step S702, a comparison module compares a first node voltage and a second node voltage and outputs a high or low level. The first node voltage is the voltage at the connection node between the power module and the load, and the second node voltage is the voltage at the connection node between the current sampling module that replicates the current of the power module in a K:1 ratio and the programmable current source.

[0034] In an exemplary embodiment, a comparison module compares a first node voltage and a second node voltage and outputs a high and low level, including: the comparison module compares a first filtered voltage generated by the first node voltage passing through a first filtering module and a second filtered voltage generated by the second node voltage passing through a second filtering module; when the first filtered voltage is less than the second filtered voltage, the comparison module outputs a high level; when the first filtered voltage is greater than the second filtered voltage, the comparison module outputs a low level.

[0035] In step S704, the control module instructs the programmable current source to adjust the current value through the output signal according to the high and low levels until the output signal stabilizes within a preset range, so that the absolute value of the difference between the current value and 1 / K of the load current value is less than a preset threshold, where K is a positive integer.

[0036] In an exemplary embodiment, the control module instructs the programmable current source to adjust the current value through the output signal according to the high and low levels until the output signal stabilizes within a preset range, including: the control module instructs the programmable current source to adjust the current value through the output signal according to the high and low levels to obtain a new second node voltage; the comparison module compares the new second node voltage with the first node voltage and outputs high and low levels, and the control module adjusts the current value in response to the high and low levels until the output signal stabilizes within the preset range.

[0037] In an exemplary embodiment, the control module instructs the programmable current source to adjust the current value through an output signal according to the high and low levels, including: when the control module receives a low level, the control module reduces the output signal to cause the programmable current source to reduce the current value; when the control module receives a high level, the control module increases the output signal to cause the programmable current source to increase the current value.

[0038] In an exemplary embodiment, the algorithm module performs an average processing on the output signal output by the control module within a preset time period.

[0039] The embodiments of the present application use closed-loop negative feedback control for time-sharing detection, eliminating the need for a multi-bit high-precision analog-to-digital converter. Instead, a single-bit comparison module and control module are required to complete the conversion from analog to digital signals. This reduces hardware resource consumption while meeting detection bandwidth requirements, resulting in a compact footprint and low cost. The chip boasts high chip integration, eliminating the need for external high-precision resistors to convert sampled current to sampled voltage. The system is suitable for low-power supply voltage scenarios, eliminating the need for an operational amplifier to clamp the drain voltages of the transistors in the power module and the current sampling module, and can operate at a low power supply voltage of 0.6V.

[0040] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, improvements, etc. made within the principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A load current detection circuit connected to a voltage stabilizing circuit core, wherein the voltage stabilizing circuit core includes a power module and a load connected thereto, characterized in that: The load current detection circuit includes: a current sampling module, a comparison module, a control module and a programmable current source, wherein: The current sampling module has an input end connected to the power module in the voltage stabilization circuit core and an output end connected to the programmable current source, and is used to replicate the current of the power module in a K:1 ratio to provide current to the programmable current source, where K is a positive integer; The comparison module is configured to compare a first node voltage and a second node voltage to generate a high or low level and output the comparison results to the control module, wherein the first node voltage is the voltage of the connection node between the power module and the load, and the second node voltage is the voltage of the connection node between the current sampling module and the programmable current source; The control module has an input end connected to the output end of the comparison module, and is used to adjust the size of the output signal according to the high and low levels output by the comparison module, and output the output signal to the programmable current source; The programmable current source has an input end connected to the output end of the control module, and is used to adjust the current value of the programmable current source according to the output signal until the output signal stabilizes within a preset range, so that the absolute value of the difference between the current value and 1 / K of the load current value is less than a preset threshold.

2. The load current detection circuit according to claim 1, wherein: Also includes: a first filtering module, connected to the comparing module, and configured to perform low-pass filtering on the first node voltage; The second filtering module is connected to the comparison module and is configured to perform low-pass filtering on the second node voltage.

3. The load current detection circuit according to claim 1, wherein: Also includes: An algorithm module is connected to the control module and is used to perform average processing on the output signal output by the control module within a preset time period.

4. The load current detection circuit according to claim 1, wherein: The power module is a single or cascaded MOS power tube.

5. The load current detection circuit according to claim 4, wherein: The current sampling module is a MOS power tube of the same type as the power module and has a size in a K:1 ratio, and is a single or cascade structure.

6. The load current detection circuit according to claim 2, wherein: The comparison module includes: a first chopping circuit, a second chopping circuit and a comparator, wherein: The first chopping circuit has an input end connected to the first filtering module and the second filtering module, and an output end connected to the input end of the comparator, and is used to swap the two input ends of the comparator in each clock cycle; The second chopping circuit has an input end connected to the output end of the comparator and an output end connected to the control module, and is used to swap the two output ends of the comparator in each clock cycle; The comparator has an output end connected to the control module and is used to compare the voltage passing through the first filtering module and the first chopping circuit with the voltage passing through the second filtering module and the first chopping circuit.

7. A load current detection method, applied to the load current detection circuit according to any one of claims 1 to 6, characterized in that: include: The comparison module compares the first node voltage and the second node voltage and outputs the high and low levels, wherein the first node voltage is the voltage of the connection node between the power module and the load, and the second node voltage is the voltage of the connection node between the current sampling module and the programmable current source, which replicates the current of the power module in a K:1 ratio; The control module instructs the programmable current source to adjust the current value through the output signal according to the high and low levels until the output signal stabilizes within the preset range, so that the absolute value of the difference between the current value and 1 / K of the load current value is less than a preset threshold, wherein K is a positive integer.

8. The method according to claim 7, characterized in that The comparison module compares the first node voltage and the second node voltage and outputs the high and low levels, including: The comparison module compares a first filtered voltage generated by the first filtering module on the first node voltage and a second filtered voltage generated by the second filtering module on the second node voltage; When the first filtered voltage is less than the second filtered voltage, the comparison module outputs a high level; When the first filtered voltage is greater than the second filtered voltage, the comparison module outputs a low level.

9. The method according to claim 7, characterized in that The control module instructs the programmable current source to adjust the current value through an output signal according to the high and low levels until the output signal stabilizes within a preset range, including: The control module instructs the programmable current source to adjust the current value through an output signal according to the high and low levels to obtain a new second node voltage; The comparison module compares the new second node voltage with the first node voltage and outputs a high or low level. The control module adjusts the current value in response to the high or low level until the output signal stabilizes within a preset range.

10. The method according to claim 7, characterized in that The control module instructs the programmable current source to adjust the current value through an output signal according to the high and low levels, including: When the control module receives a low level, the control module reduces the output signal to make the programmable current source reduce the current value; When the control module receives a high level, the control module increases the output signal to enable the programmable current source to increase the current value.

11. The method according to claim 7, characterized in that The method further comprises: The algorithm module performs average processing on the output signal output by the control module within a preset time period.

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