WO2018060756A1

WO2018060756A1 - Multi-level over-current protection for switched-mode power supply

Info

Publication number: WO2018060756A1
Application number: PCT/IB2016/055810
Authority: WO
Inventors: Torbjörn HOLMBERG; Andreas Larsson; Jonas Malmberg; Fredrik Wahledow
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ
Priority date: 2016-09-29
Filing date: 2016-09-29
Publication date: 2018-04-05

Abstract

A controller including over-current protection operable with a switched-mode 5 power supply and method of operating the same. In an embodiment, the controller is configured to provide an over-current protection fault signal when an operating parameter of the switched-mode power supply exceeds a static over-current protection level, and provide the over-current protection fault signal when the operating parameter of the switched-mode power supply exceeds a dynamic over-current protection level for a time 10 period greater than a dynamic time interval.

Description

MULTI-LEVEL OVER-CURRENT PROTECTION

FOR SWITCHED-MODE POWER SUPPLY

TECHNICAL FIELD

The present invention is directed, in general, to the field of power electronics and, more specifically, to a controller including over-current protection operable with a switched-mode power supply and method of operating the same.

BACKGROUND

A switched-mode power supply can be applied to a diverse range of applications by virtue of its dimensions, weight and high efficiency. For example, switched-mode power supplies are widely used in personal computers and portable electronic devices such as cellphones. The switched-mode power supplies can also be applied to data centers and base stations to facilitate data communications and telecommunications. A switching device or power switch (e.g. , a metal-oxide semiconductor field-effect transistor ("MOSFET")) of a power train of the switched-mode power supply is controlled to convert an input voltage to a desired output voltage. A frequency (also referred to as a "switching frequency") and duty cycle of the switching device is adjusted using a feedback signal to convert the input voltage to the desired output voltage.

The controllers for switched-mode power supplies such as point of load ("POL") regulators provide regulation as set forth above and general safeguards such as average or peak static over-current protection ("OCP"). Existing types of over-current protection are based on current measurements that depend on a switching period Ts of the switched- mode power supply, which is typically in the range of 1-100 microseconds ("μ^δ")·

Existing over-current protection functionality acts on an inductor current II in an inductor (e.g. , an output filter inductor) of the switched-mode power supply. Average static over- current protection generally acts on an average level of inductor current Lavg, whereas peak static over-current protection generally acts on a peak level of inductor current Lpeak. While the static level of over-current protection has been sufficient to date, it would be beneficial to extend the over-current protection functionality to handle the new applications for the switched-mode power supplies that lie ahead. SUMMARY

These and other problems are generally solved or circumvented, and technical advantages are generally achieved, by advantageous embodiments of the present invention for a controller including over-current protection operable with a switched- mode power supply and method of operating the same. In an embodiment, the controller is configured to provide an over-current protection fault signal when an operating parameter of the switched-mode power supply exceeds a static over-current protection level, and provide the over-current protection fault signal when the operating parameter of the switched-mode power supply exceeds a dynamic over-current protection level for a time period greater than a dynamic time interval.

The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter, which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures or processes for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

FIGURE 1 illustrates a schematic diagram of an embodiment of a switched-mode power supply;

FIGURE 2 illustrates a graphical representation demonstrating representative characteristics of the inductor current through the inductor of FIGURE 1 ;

FIGURES 3 to 7 illustrate graphical representations of embodiments of an output current of a switched-mode power supply versus time;

FIGURES 8 to 10 illustrated logic diagrams of embodiments of a protection circuit; and FIGURE 11 illustrates a flow diagram of an embodiment of a method of operating a switched-mode power supply.

Corresponding numerals and symbols in the different figures generally refer to corresponding parts unless otherwise indicated, and may not be redescribed in the interest of brevity after the first instance. The FIGURES are drawn to illustrate the relevant aspects of exemplary embodiments.

DETAILED DESCRIPTION

The making and using of the present exemplary embodiments are discussed in detail below. It should be appreciated, however, that the embodiments provide many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific embodiments discussed are merely illustrative of specific ways to make and use the systems, subsystems, and modules associated with over-current protection for a switched-mode power supply.

A system will be described herein with respect to exemplary embodiments in a specific context, namely, a controller including over-current protection operable with a switched-mode power supply. While the principles will be described in the environment of a switched-mode power supply, any environment such as a motor controller or power amplifier that may benefit from such a system and method that enables these

functionalities is well within the broad scope of the present disclosure.

Existing implementations of the static over-current protection may have a configurable fault counter, so that over-current protection is triggered after a number "n" of detected faults in an uninterrupted sequence, where "n" is an integer with a value between 1 and N. A typical value of N is in the range of 15 or 30. A configurable fault counter increases the over-current protection delay time range from 1 to 100 μ8 to a range οί Ν μ8 ΐο 100·Ν μ8.

Due to increased level of "on-demand" services in both data communications and telecommunications supported by high performing and rapid response loads such as field programmable gate arrays ("FPGAs"), microprocessor control units ("MCUs") and application specific integrated circuits ("ASICs"), peak power needs for a much longer time than existing over-current protection functionalities are often needed. By having only static over-current protection functionality in a peak power application, power level utilization of the switched-mode power supply is reduced to a level lower than otherwise possible. Hence, there is a need for additional over-current protection functionality that can tolerate peak currents for time periods that might be, without limitation, 5 - 100 milliseconds ("ms", and longer is possible up to several seconds) and still operate within a specified thermal design power ("TDP") level, and also work in combination with existing solutions.

It is highly desirable, therefore, to develop an over-current protection strategy operable in switch-mode power supplies that can provide both over-current and thermal protection over a wider range of operating conditions. An over-current protection strategy that addresses the aforementioned needs may enhance utilization of switch-mode power supplies without otherwise disturbing the design thereof.

Referring initially to FIGURE 1, illustrated is a schematic diagram of an embodiment of a switched-mode power supply 100. The switched-mode power supply 100 receives an input current I;_n and converts a direct current ("dc") input voltage V;_n (from a source of electrical power) to a desired dc output voltage V_out. The output voltage Vout is applied across a load (designated "LD") connected in parallel with an output capacitor C_out. An output current I_out is split between the output capacitor C_out (receiving a capacitor current Ic) and the load LD (receiving a load current ILD). The switched-mode power supply 100 includes an inductor L (with an inductor current II therethrough), the output capacitor Cout and first and second power switches (also referred to as "switching devices") Ql , Q2. The switched-mode power supply 100 also includes a controller 110 (including a processor ("PR") 120 and memory ("M") 130) that controls the first and second power switches Ql , Q2 to regulate the output voltage V_out of the switched-mode power supply 100.

The controller 110 applies the control signals Csl , Cs2 at an appropriate frequency (e.g. , 300 kilohertz ("kHz")) to control terminals of the first and second power switches Ql , Q2, respectively. The controller 110 regulates the output voltage V_out by adjusting the duty cycles D, 1-D of the control signals Csl , Cs2 for the first and second power switches Ql , Q2, respectively, as a function of the output current I_out and/or the output voltage V_out- The controller 110 is coupled to first and second current-sense devices 140, 145 that provide the inductor current II and the output current I respectively, to a protection circuit (e.g. , an over-current protection ("OCP") circuit) 150 embodied in the processor 120 and memory 130 of the controller 110. The controller 110 also receives the output voltage V In addition to regulating the output voltage V the controller 110 performs other functions including over-current protection for the switched-mode power supply 100 based on, without limitation, the inductor current II, the output current I and/or the output voltage V

The processor 120 may be embodied as any type of processor and associated circuitry configured to perform one or more of the functions described herein. For example, the processor 120 may be embodied as or otherwise include a single or multi- core processor, an application specific integrated circuit, a field-programmable gate array, a collection of logic devices, or other circuits. The memory 130 may be embodied as read-only memory devices and/or random access memory devices. For example, the memory 130 may be embodied as or otherwise include dynamic random access memory devices ("DRAM"), synchronous dynamic random access memory devices ("SDRAM"), double-data rate dynamic random access memory devices ("DDR SDRAM"), and/or other volatile or non-volatile memory devices. The memory 130 may have stored therein programs including a plurality of instructions or computer program code for execution by the processor 120 to control particular functions of the power converter 100 as discussed in more detail below.

The over-current protection includes a static component (referred to as static over- current protection ("SOCP")) and a dynamic component (referred to as dynamic over- current protection ("DOCP")). The over-current protection circuit 150 in the controller 110 of FIGURE 1 introduced above incorporates the static and dynamic components into the over-current protection. The dynamic functionality may be enabled or disabled. When the dynamic component is disabled, then only the static over-current protection remains active.

As will become more apparent, an advantage with the dynamic functionality is that the controller may allow the load to draw higher current levels from the switched- mode power supply for controlled periods of time without entering an over-current protection fault mode. Thus, a processor within a server of a data center (data communications application) or base station (telecommunications application) powered by the switched-mode power supply can draw higher current levels for controlled periods of time to perform selected tasks. In other words, the dynamic functionality delays the over-current protection fault mode for an acceptable time interval. That being said, if a peak value of the monitored parameter such as the inductor current II exceed a static over-current protection level, then the over-current protection fault mode is triggered regardless of the dynamic over-current protection level.

For the discussion that follows, several parameters will be employed to describe the multi-level over-current protection. The static and dynamic over-current protection levels are designated IOCP_S, IOCP_D, respectively. A difference between the static and dynamic over-current protection levels is designated AIOCP ( = IOCP_S - IOCP_D) and a dynamic time interval allocated to the dynamic over-current protection level is designated

AtoCP_D.

An over-current protection fault can be triggered by two events, either a current such as an inductor current II remains above the dynamic over-current protection level IOCP_D for the dynamic time interval Atocp_D or an instantaneous current crosses the static over-current protection level IOCP_S. For the dynamic over-current protection, the controller will allow a temporary over-current protection depending on the settings associated therewith.

Turning now to FIGURE 2, illustrated is a graphical representation demonstrating representative characteristics of the inductor current II through the inductor L of FIGURE 1. The graphical representation illustrates a peak inductor current iLpeak and an average inductor current Lavg as a function of time "T". A switching period Ts of the switched- mode power supply 100 is partitioned into a charge phase ("AICHARGE") commensurate with a duty cycle D produced by the controller 1 10 and a discharge phase ("AIDISCHARGE") commensurate with a complementary duty cycle 1-D produced by the controller 1 10. Even though the peak inductor current Lpeak reaches higher current levels, it is possible to avoid an over-current protection fault as long as the upper peaks are limited to short time intervals (e.g. , the dynamic time interval Atocp_D) in accordance with a dynamic over- current protection level IOCP_D- Turning now to FIGURE 3, illustrated is a graphical representation of an embodiment of an output current I_out of a switched-mode power supply versus time "t". The graphical representation includes static and dynamic over-current protection levels IOCP_S, IOCP_D, and a difference AIOCP therebetween. As illustrated, the output current I_out crosses the dynamic over-current protection level IOCP_D, but not the static over-current protection level IOCP_S- The output current I_out remains above the dynamic over-current protection level IOCP_D for a time period ΔΤ that is less than the dynamic time interval Atocp_D allocated to the dynamic over-current protection level IOCP_D (i.e., ΔΤ < Atocp_D). As a result, over-current protection is not triggered for the switched-mode power supply.

Turning now to FIGURE 4, illustrated is a graphical representation of an embodiment of an output current I_out of a switched-mode power supply versus time "t". The graphical representation includes static and dynamic over-current protection levels IOCP_S, IOCP_D, and a difference AIOCP therebetween. As illustrated, the output current I_out crosses the dynamic over-current protection level IOCP_D, but not the static over-current protection level IOCP_S. The output current I_out remains above the dynamic over-current protection level IOCP_D for a time period ΔΤ that is greater than the dynamic time interval Atocp_D allocated to the dynamic over-current protection level IOCP_D (i.e., ΔΤ > Atocp_D). As a result, over-current protection is triggered for the switched-mode power supply.

Turning now to FIGURE 5, illustrated is a graphical representation of an embodiment of an output current I_out of a switched-mode power supply versus time "t". The graphical representation includes static and dynamic over-current protection levels IOCP_S, IOCP_D, and a difference AIOCP therebetween. As illustrated, the output current I_out crosses the dynamic over-current protection level IOCP_D and the static over-current protection level IOCP_S- The output current I_out remains above the dynamic over-current protection level IOCP_D for a time period ΔΤ that is less than the dynamic time interval

Atocp_D allocated to the dynamic over-current protection level IOCP_D (i.e., ΔΤ < Atocp_D). Since the output current I_out crossed the static over-current protection level IOCP_S, (i.e. , I_out > IOCP_S), however, the over-current protection is triggered for the switched-mode power supply.

Turning now to FIGURE 6, illustrated is a graphical representation of an embodiment of an output current I_out of a switched-mode power supply versus time "t". The graphical representation includes static and dynamic over-current protection levels IOCP_S, IOCP_D, and a difference AIOCP therebetween. As illustrated, the output current I_out crosses the dynamic over-current protection level IOCP_D, but not the static over-current protection level IOCP_S- The output current I_out remains above the dynamic over-current protection level IOCP_D for a time period ΔΤ that is less than the dynamic time interval Atocp_D allocated to the dynamic over-current protection level IOCP_D (i.e. , ΔΤ < Atocp_D). Thereafter, the output current I_out crosses the dynamic over-current protection level IOCP_D at a second time t₂, but, again, not the static over-current protection level IOCP_S- Since the second occurrence of the output current I_out crossing the dynamic over-current protection level IOCP_D (at the second time t₂) is less than a blanking time tbiank (i.e. , t₂ < tbiank), the over-current protection is triggered for the switched-mode power supply.

Turning now to FIGURE 7, illustrated is a graphical representation of an embodiment of an output current I_out of a switched-mode power supply versus time "t". The graphical representation includes static and dynamic over-current protection levels IOCP_S, IOCP_D, and a difference AIOCP therebetween. As illustrated, the output current I_out crosses the dynamic over-current protection level IOCP_D, but not the static over-current protection level IOCP_S. The output current I_out remains above the dynamic over-current protection level IOCP_D for a time period ΔΤ that is less than the dynamic time interval Atocp_D allocated to the dynamic over-current protection level IOCP_D (i.e. , ΔΤ < Atocp_D). Thereafter, the output current I_out crosses the dynamic over-current protection level IOCP_D at a second time t₂, but, again, not the static over-current protection level IOCP_S- Since the second occurrence of the output current I_out crossing the dynamic over-current protection level IOCP_D (at the second time t₂) is greater than a blanking time tbiank (i.e. , t₂ > tbiank), the over-current protection is not triggered for the switched-mode power supply.

Thus, over-current protection for a switched-mode power supply can be triggered under different conditions and circumstances. If the operating parameter (e.g. , the output current I_out) of the switched-mode power supply crosses a static over-current protection level IOCP_S, then the over-current protection is triggered. With respect to the dynamic functionality (and assuming the static over-current protection is not triggered), if the operating parameter of the switched-mode power supply crosses a dynamic over-current protection level IOCP_D for a time period ΔΤ that is greater than a dynamic time interval Atocp_D allocated to the dynamic over-current protection level IOCP_D (i.e. , ΔΤ > Atocp_D), then the over-current protection is triggered. Even if the time period ΔΤ is less than the dynamic time interval Atocp_D allocated to the dynamic over-current protection level IOCP_D (i.e. , ΔΤ < Atocp_D), the over-current protection can be triggered if the operating parameter crosses the dynamic over-current protection level IOCP_D at a second time t2 being less than a blanking time tbiank-

Of course, the trigger points including, without limitation, the static and dynamic over-current protection levels IOCP_S, IOCP_D, the dynamic time interval Atocp_D and the blanking time tbiank are configurable based on factors such as the application and type of switched-mode power supply. For instance, if the switched-mode power supply is a point-of-load regulator, the blanking time tbiank (and the dynamic over-current protection setpoints in general) should be selected to take into account the thermal design power ("TDP") characteristics of the point-of-load regulator, especially in view of the application.

Turning now to FIGURE 8, illustrated is a logic diagram of an embodiment of a protection circuit (e.g. , an over-current protection circuit 800) configurable with first and second dynamic over-current protection levels OCP_Dl , OCP_D2 associated with first and second over-current protection subsystems 805, 840, respectively. An operating parameter such as an output current I_out of a switched-mode power supply is provided to a nonin verting input of a comparator 810. An inverting input of the comparator 810 receives a FAULT_LEVELOCP_DI signal associated with the first dynamic over-current protection level OCP_D l. The output current I_out is also provided to an inverting input of a comparator 815. A nonin verting input of the comparator 815 receives a WARN_ LEVELOCP_DI signal to implement logic associated with a first dynamic time interval Atocp_Di associated with the first dynamic over-current protection level OCP_Dl .

An output of the comparator 810 is provided to a start terminal of a timer 820, and an output of the comparator 815 is provided to stop and reset terminals of the timer 820. An output of the timer 820 is provided to a nonin verting input of a comparator 825, and an inverting input of the comparator 825 receives the first dynamic time interval Atocp_Di- An output of the comparator 825 and an Enableocp_Di signal associated with the first dynamic over-current protection level OCP_Dl are provided to an AND gate 830. An output of the AND gate 830 is provided to an OR gate 835, which ultimately sets an OCP_FAULT signal representing an over-current protection fault for the switched-mode power supply. Thus, the over-current protection circuit 800 implements the

OCP_FAULT signal if the output current I_out exceeds the first dynamic over-current protection level OCP_D 1 for a time period ΔΤι greater than the first dynamic time interval Atocp_Di in connection with the first over-current protection subsystem 805. In a similar way, the over-current protection circuit 800 implements the OCP_FAULT signal if the output current I_out exceeds the second dynamic over-current protection level OCP_D2 for a time period ΔΤ2 greater than a second dynamic time interval Atocp_D2 in connection with the second over-current protection subsystem 840. The first and second dynamic over-current protection levels OCP_Dl, OCP_D2, and the first and second dynamic time intervals Atocp_Di, Atocp_D2 are typically different.

To implement a blanking time tbiank between successive occurrences that the output current I_out exceeds the first and second dynamic over-current protection levels OCP_Dl, OCP_D2, the outputs of the comparators 810, 815 are provided to an input of an OR gate 845, and the outputs from respective comparators from the second over- current protection subsystem 840 are provided to another input of the OR gate 845. An output of the OR gate 845 is provided to a start terminal of a timer 850, a set terminal of a set-reset flip-flop 855, and an input of an AND gate 860. An output of the timer 850 is provided to a noninverting input of a comparator 865, and an inverting input of the comparator 865 receives the blanking time tbiank. An output of the comparator 865 is provided to a reset terminal of the set-reset flip-flop 855, and to stop and reset terminals of the timer 850. An output of the set-reset flip-flop 855 is provided to another input of the AND gate 860, and an output of the AND gate 860 is provided to the OR gate 835. Thus, the over-current protection circuit 800 implements the OCP_FAULT signal if the output current I_out exceeds the first or second dynamic over-current protection levels OCP_Dl, OCP-D2 for a second time within the blanking time tbiank.

Regarding the static functionality, the output current I_out is provided to a noninverting input of a comparator 870. An inverting input of the comparator 870 receives a FAULT_LEVELOCP_S signal associated with a static over-current protection level OCP_S. The output current I_out is also provided to an inverting input of a comparator 875. A noninverting input of the comparator 875 receives a WARN_ LEVELOCP_S signal associated with the static over-current protection level OCP_S. An output of the comparator 870 is provided to an input of an AND gate 880, and an output of the comparator 875 is provided to another input of the AND gate 880. An output of the AND gate 880 is provided to the OR gate 835. Thus, the over-current protection circuit 800 implements the OCP_FAULT signal if the output current I_out exceeds the static over-current protection level OCP_S.

Of course, the number of dynamic over-current protection levels can be increased to depending on the type of switched-mode power supply and/or the application therefor. Also, the dynamic over-current protection subsystems can be disabled to rely solely on the static over-current protection, or ones of the dynamic over-current protection subsystems can be disabled to selectively activate the dynamic over-current protection. Also, the over-current protection circuit can be implemented in any type of switched- mode power supply such as, without limitation, isolated or non-isolated dc/dc converters, intermediate bus converters ("IBCs"), and isolated and direct conversion point-of-load regulators. Also, to limit the number of dynamic over-current protection faults, a fault counter may be added to the over-current protection circuit. An over-current protection fault will then be triggered if the number of faults becomes equal to the (configurable) number of a maximum number of over-current protection allowable faults allowed. For a better understanding of a fault counter, see International Publication No. WO

2013/085442 (also referred to as Application No. PCT/SE2011/051492) entitled "Method for Operating a Power Converter Module and Device Therefor," to Persson, et ah, published June 13, 2013, which is incorporated herein by reference.

For board-mounted power or other dc/dc powered applications in tough thermal environments designed for a thermal design (average) power, a limiting parameter is actually the power or power loss rather than the output current. That is, the output voltage Vout times the output current I_out (i.e., V_out x lout) is the level that may need to be protected. Using the ideas introduced hereinabove, an additional over-power protection ("OPP") can be implemented. Since the output power P_out equals the output voltage V_out times the output current I_out and power loss Pi_oss is a function of the output power P_out, the over-power protection can be defined and configured by a factor of V_out/l volt (at V_out = 1 volt, Pout = lout with units of watts ("W")). Turning now to FIGURE 9, illustrated is a logic diagram of an embodiment of a protection circuit (e.g. , an over-power protection circuit 900). See explanation above for a discussion of similar components of the over-power protection circuit 900 of FIGURE 9 and the over-current protection circuit 800 of FIGURE 8. By knowing or having a model for power loss Pi_oss as a function of output power P_out and using an operating parameter available in the switched-mode power supply, then both a static and a dynamic overpower protection can be implemented therefor.

As illustrated in FIGURE 9, an operating parameter such as output current I_out is provided to a multiplier 910. The multiplier 910 multiplies the output current I_out by an output voltage V_out of the switched-mode power supply to obtain an output power P_out- A logic device 920 implements a function that relates the power loss Pi_oss to the output power Pout of the switched-mode power supply. The static and dynamic protections can thereafter be implemented as set forth above with respect to FIGURE 8.

Turning now to FIGURE 10, illustrated is a logic diagram of an embodiment of a protection circuit (e.g. , an over-power protection circuit 1000). See explanation above for a discussion of similar components of the over-power protection circuit 1000 of FIGURE 10 and the over-current protection circuit 800 of FIGURE 8. As an alternative to the over-power protection circuit 900 of FIGURE 9, the calculation of the output power P_out and related function can be accounted for by the FAULT_LEVELOCP_D and WARN_ LEVELOCP_D signals, thereby reducing propagation time. As a result, the output current lout is connected to the comparators as illustrated and described with respect to FIGURE 8.

Turning now to FIGURE 11 , illustrated is a flow diagram of an embodiment of a method of operating a switched-mode power supply (designated "SMPS")- The method begins at a start step or module 1100. At the step or module 1105, the method includes providing a control signal(s) to a power switch(es) to regulate an output characteristic (e.g. , an output voltage ) of the switched-mode power supply. At the step or module 1110, the method includes receiving an operating parameter of the switched-mode power supply via, for instance, a current-sense device. The operating parameter may include, without limitation, an output current, an output voltage, an inductor current of an inductor, and/or an output power of the switched-mode power supply. The method continues by providing an over-current protection fault (designated "OCP_FAULT") signal when the operating parameter of the switched-mode power supply exceeds a static over-current protection level (designated "OCP_S") at the step or module 1115. At a decisional step or module 1120, the method determines if dynamic over-current protection should be enabled. If the dynamic over-current protection should not be enabled, the method ends at a step or module 1125, otherwise the method continues by enabling application of a dynamic over-current protection level (designated "OCP_D") to the operating parameter of the switched-mode power supply at a step or module 1130. At a step or module 1135, the method includes providing the over-current protection fault signal when the operating parameter of the switched-mode power supply exceeds the dynamic over-current protection level for a time period (designated "ΔΤ") greater than a dynamic time interval (designated "Atocp_D")- At a step or module 1140, the method includes providing the over-current protection fault signal when the operating parameter of the switched-mode power supply exceeds the dynamic over-current protection level multiple times within a blanking time interval (designated "tbiank")-

At a decisional step or module 1145, the method determines if another (a second) dynamic over-current protection level (designated "OCP_D2") should be applied to the switched-mode power supply. If the second dynamic over-current protection level should not be applied, the method ends at the step or module 1125, otherwise the method continues by providing the over-current protection fault signal when the operating parameter of the switched-mode power supply exceeds the second dynamic over-current protection level for another time period (designated "ΔΤ2") greater than another dynamic time interval (designated "Atocp_D2") at a step or module 1150. As an example, the dynamic over-current protection level is different than the another dynamic over-current protection level (OCP_D2), and the dynamic time interval is different than the another dynamic time interval. At a step or module 1155, the method includes providing the over-current protection fault signal when the operating parameter of the switched-mode power supply exceeds the second dynamic over-current protection level multiple times within another blanking time interval (designated "tbiank2")- At a decisional step or module 1160, the method determines if another (an "n^th") dynamic over-current protection level (designated "OCP_Dn") should be applied to the switched-mode power supply. If the third dynamic over-current protection level should not be applied, the method ends at the step or module 1125, otherwise the method continues by providing the over-current protection fault signal when the operating parameter of the switched-mode power supply exceeds the third dynamic over-current protection level for yet another time period (designated "ΔΤ_η") greater than yet another dynamic time interval (designated "Atocp_Dn") at a step or module 1165. At a step or module 1170, the method includes providing the over-current protection fault signal when the operating parameter of the switched-mode power supply exceeds the third dynamic over-current protection level multiple times within yet another blanking time interval (designated "tbiankn")- While the method thereafter ends at the step or module 1125, it should be understood that the method may iterate on ones of the dynamic over-current protection levels or provide yet another dynamic over-current protection level as a safeguard for the switched-mode power supply.

Thus, the present disclosure introduces a switched-mode power supply (100) including at least one power switch (Ql, Q2) coupled to an input of the switched-mode power supply (100) and an inductor (L) interposed between the at least one power switch (Ql, Q2) and an output of the switched-mode power supply (100). A controller (110) of the switched-mode power supply (100) is configured to provide a control signal (Csl, Cs2) to the at least one power switch (Ql, Q2) to regulate an output voltage (V_out) of the switched-mode power supply (100). In the appropriate applications, the controller (110) is configured to enable application of a dynamic over-current protection level (OCP_D) to an operating parameter (I_out) of said switched-mode power supply (100). The operating parameter may include an output current (I_out) of the switched-mode power supply, an output voltage (V_out) of the switched-mode power supply, an inductor current (II) of the inductor (L) of the switched-mode power supply, and/or an output power (P_out) of the switched-mode power supply.

The controller (110) is configured to receive the operating parameter (I_out) via, for instance, a current-sense device (145, in the case of a current) and provide an over-current protection fault (OCP_FAULT) signal when the operating parameter (I_out) of the switched-mode power supply (100) exceeds a static over-current protection level (OCP_S), and provide the over-current protection fault (OCP_FAULT) signal when the operating parameter (I_out) of the switched-mode power supply (100) exceeds a dynamic over-current protection level (OCP_D) for a time period (ΔΤ) greater than a dynamic time interval (Atocp_D). The controller (110) is also configured to provide the over-current protection fault (OCP_FAULT) signal when the operating parameter (I_out) of the switched-mode power supply (100) exceeds the dynamic over-current protection level (OCP_D) multiple times within a blanking time interval (tbiank).

In another embodiment, the controller (110) is further configured to provide the over-current protection fault (OCP_FAULT) signal when the operating parameter (I_out) of the switched-mode power supply (100) exceeds another dynamic over-current protection level (OCP_D2) for another time period (ΔΤ₂) greater than another dynamic time interval (Atocp_D2). In accordance therewith, the controller (110) is configured to provide the over-current protection fault (OCP_FAULT) signal when the operating parameter (I_out) of the switched-mode power supply (100) exceeds the another dynamic over-current protection level (OCP_D2) multiple times within a blanking time interval (tbiank2).

Typically, but not necessarily, the dynamic over-current protection level (OCP_D) is different than the another dynamic over-current protection level (OCP_D2), and the dynamic time interval (Atocp_D) is different than the another dynamic time interval

(Atocp_D2). Thus, the controller (110) is configured to provide the over-current protection fault (OCP_FAULT) signal when the operating parameter (I_out) of the switched-mode power supply (100) exceeds one of a plurality of dynamic over-current protection levels (OCP_Dn) for a corresponding time period (ΔΤ_η) greater than a respective dynamic time interval (Atocp_Dn).

The foregoing description of embodiments of the present proposed solution has been presented for the purpose of illustration and description. It is not intended to be exhaustive or to limit the proposed solution to the present form disclosed. Alternations, modifications and variations can be made without departing from the spirit and scope of the present proposed solution.

As described above, the exemplary embodiment provides both a method and corresponding apparatus consisting of various modules providing functionality for performing the steps of the method. The modules may be implemented as hardware (embodied in one or more chips including an integrated circuit such as an application specific integrated circuit), or may be implemented as software or firmware for execution by a processor. In particular, in the case of firmware or software, the exemplary embodiment can be provided as a computer program product including a computer readable storage medium embodying computer program code (i.e., software or firmware) thereon for execution by the computer processor. The computer readable storage medium may be non-transitory (e.g., magnetic disks; optical disks; read only memory; flash memory devices; phase-change memory) or transitory (e.g., electrical, optical, acoustical or other forms of propagated signals-such as carrier waves, infrared signals, digital signals, etc.). The coupling of a processor and other components is typically through one or more busses or bridges (also termed bus controllers). The storage device and signals carrying digital traffic respectively represent one or more non-transitory or transitory computer readable storage medium. Thus, the storage device of a given electronic device typically stores code and/or data for execution on the set of one or more processors of that electronic device such as a controller.

Although the embodiments and its advantages have been described in detail, it should be understood that various changes, substitutions, and alterations can be made herein without departing from the spirit and scope thereof as defined by the appended claims. For example, many of the features and functions discussed above can be implemented in software, hardware, or firmware, or a combination thereof. Also, many of the features, functions, and steps of operating the same may be reordered, omitted, added, etc., and still fall within the broad scope of the various embodiments.

Moreover, the scope of the various embodiments is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed, that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized as well.

Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.

Claims

IN THE CLAIMS:

1. A controller (110) for use with a switched-mode power supply (100), comprising:

a processor (120); and

a memory (130) including computer program code, wherein said processor (120), said memory (130), and said computer program code are collectively operable to:

provide an over-current protection fault (OCP_FAULT) signal when an operating parameter (I_out) of said switched-mode power supply (100) exceeds a static over-current protection level (OCP_S); and

provide said over-current protection fault (OCP_FAULT) signal when said operating parameter (I_out) of said switched-mode power supply (100) exceeds a dynamic over-current protection level (OCP_D) for a time period (ΔΤ) greater than a dynamic time interval (Atocp_D).

2. The controller (110) as recited in Claim 1 wherein said memory (130) and said computer program code are further configured to, with said processor (120) cause said controller (110) to provide said over-current protection fault (OCP_FAULT) signal when said operating parameter (I_out) of said switched-mode power supply (100) exceeds said dynamic over-current protection level (OCP_D) multiple times within a blanking time interval (tbiank).

3. The controller (110) as recited in Claim 1 wherein said memory (130) and said computer program code are further configured to, with said processor (120) cause said controller (110) to provide said over-current protection fault (OCP_FAULT) signal when said operating parameter (I_out) of said switched-mode power supply (100) exceeds another dynamic over-current protection level (OCP_D2) for another time period (ΔΤ₂) greater than another dynamic time interval (Atocp_D2).

4. The controller (110) as recited in Claim 3 wherein said memory (130) and said computer program code are further configured to, with said processor (120) cause said controller (110) to provide said over-current protection fault (OCP_FAULT) signal when said operating parameter (I_out) of said switched-mode power supply (100) exceeds said another dynamic over-current protection level (OCP_D2) multiple times within a blanking time interval (tbiank2).

5. The controller (110) as recited in Claim 3 wherein said dynamic over- current protection level (OCP_D) is different than said another dynamic over-current protection level (OCP_D2), and said dynamic time interval (Atocp_D) is different than said another dynamic time interval (Atocp_D2).

6. The controller (110) as recited in Claim 1 wherein said memory (130) and said computer program code are further configured to, with said processor (120) cause said controller (110) to provide said over-current protection fault (OCP_FAULT) signal when said operating parameter (I_out) of said switched-mode power supply (100) exceeds one of a plurality of dynamic over-current protection levels (OCP_Dn) for a

corresponding time period (ΔΤ_η) greater than a respective dynamic time interval

(AtoCP_Dn).

7. The controller (110) as recited in Claim 1 wherein said memory (130) and said computer program code are further configured to, with said processor (120) cause said controller (110) to enable application of said dynamic over-current protection level (OCP_D) to said operating parameter (I_out) of said switched-mode power supply (100).

8. The controller (110) as recited in Claim 1 wherein said memory (130) and said computer program code are further configured to, with said processor (120) cause said controller (110) to receive said operating parameter (I_out) via a current-sense device (145).

9. The controller (110) as recited in Claim 1 wherein said memory (130) and said computer program code are further configured to, with said processor (120) cause said controller (110) to provide a control signal (Csl) to a power switch (Ql) to regulate an output voltage (V_out) of said switched-mode power supply (100).

10. The controller (110) as recited in Claim 1 wherein said operating parameter of said switched-mode power supply (100) is selected from the group consisting of:

an output current (I_out) of said switched-mode power supply,

an output voltage (V_out) of said switched-mode power supply,

an inductor current (II) of an inductor (L) of said switched-mode power supply, and

an output power (P_out) of said switched-mode power supply.

11. A method of operating a switched-mode power supply (100), comprising: providing (1115) an over-current protection fault (OCP_FAULT) signal when an operating parameter (I_out) of said switched-mode power supply (100) exceeds a static over-current protection level (OCP_S); and

providing (1135) said over-current protection fault (OCP_FAULT) signal when said operating parameter (I_out) of said switched-mode power supply (100) exceeds a dynamic over-current protection level (OCP_D) for a time period (ΔΤ) greater than a dynamic time interval (Atocp_D).

12. The method as recited in Claim 11 further comprising providing (1140) said over-current protection fault (OCP_FAULT) signal when said operating parameter

(lout) of said switched-mode power supply (100) exceeds said dynamic over-current protection level (OCP_D) multiple times within a blanking time interval (tbiank).

13. The method as recited in Claim 11 further comprising providing (1150) said over-current protection fault (OCP_FAULT) signal when said operating parameter (lout) of said switched-mode power supply (100) exceeds another dynamic over-current protection level (OCP_D2) for another time period (ΔΤ₂) greater than another dynamic time interval (Atocp_D2).

14. The method as recited in Claim 13 further comprising providing (1155) said over-current protection fault (OCP_FAULT) signal when said operating parameter (lout) of said switched-mode power supply (100) exceeds said another dynamic over- current protection level (OCP_D2) multiple times within a blanking time interval (tbiank2).

15. The method as recited in Claim 13 wherein said dynamic over-current protection level (OCP_D) is different than said another dynamic over-current protection level (OCP_D2), and said dynamic time interval (Atocp_D) is different than said another dynamic time interval (Atocp_D2).

16. The method as recited in Claim 11 further comprising providing (1165) said over-current protection fault (OCP_FAULT) signal when said operating parameter (lout) of said switched-mode power supply (100) exceeds one of a plurality of dynamic over-current protection levels (OCP_Dn) for a corresponding time period (ΔΤ_η) greater than a respective dynamic time interval (Atocp_Dn).

17. The method as recited in Claim 11 further comprising enabling (1130) application of said dynamic over-current protection level (OCP_D) to said operating parameter (I_out) of said switched-mode power supply (100).

18. The method as recited in Claim 11 further comprising receiving (1110) said operating parameter (I_out) via a current-sense device (145).

19. The method as recited in Claim 11 further comprising providing (1105) a control signal (Csl) to a power switch (Ql) to regulate an output voltage (V_out) of said switched-mode power supply (100).

20. The method as recited in Claim 11 wherein said operating parameter of said switched-mode power supply (100) is selected from the group consisting of:

an output current (I_out) of said switched-mode power supply,

an output voltage (V_out) of said switched-mode power supply,

an output power (P_out) of said switched-mode power supply.

21. A switched-mode power supply (100), comprising:

at least one power switch (Ql , Q2) coupled to an input of said switched-mode power supply (100);

an inductor (L) interposed between said at least one power switch (Ql , Q2) and an output of said switched-mode power supply (100); and

a controller (110) configured to:

provide an over-current protection fault (OCP_FAULT) signal when an operating parameter (I_out) of said switched-mode power supply (100) exceeds a static over-current protection level (OCP_S), and

22. The switched-mode power supply (100) as recited in Claim 21 wherein said controller (110) is further configured to provide said over-current protection fault

(OCP_FAULT) signal when said operating parameter (I_out) of said switched-mode power supply (100) exceeds said dynamic over-current protection level (OCP_D) multiple times within a blanking time interval (tbiank).

23. The switched-mode power supply (100) as recited in Claim 21 wherein said controller (110) is further configured to provide said over-current protection fault (OCP_FAULT) signal when said operating parameter (I_out) of said switched-mode power supply (100) exceeds another dynamic over-current protection level (OCP_D2) for another time period (ΔΤ₂) greater than another dynamic time interval (Atocp_D2).

24. The switched-mode power supply (100) as recited in Claim 23 wherein said controller (110) is further configured to provide said over-current protection fault (OCP_FAULT) signal when said operating parameter (I_out) of said switched-mode power supply (100) exceeds said another dynamic over-current protection level (OCP_D2) multiple times within a blanking time interval (tbiank2).

25. The switched-mode power supply (100) as recited in Claim 23 wherein said dynamic over-current protection level (OCP_D) is different than said another dynamic over-current protection level (OCP_D2), and said dynamic time interval (Atocp_D) is different than said another dynamic time interval (Atocp_D2).

26. The switched-mode power supply (100) as recited in Claim 21 wherein said controller (110) is further configured to provide said over-current protection fault (OCP_FAULT) signal when said operating parameter (I_out) of said switched-mode power supply (100) exceeds one of a plurality of dynamic over-current protection levels

(OCP_Dn) for a corresponding time period (ΔΤ_η) greater than a respective dynamic time interval (Atocp_Dn).

27. The switched-mode power supply (100) as recited in Claim 21 wherein said controller (110) is further configured to enable application of said dynamic over- current protection level (OCP_D) to said operating parameter (I_out) of said switched-mode power supply (100).

28. The switched-mode power supply (100) as recited in Claim 21 wherein said controller (110) is further configured to receive said operating parameter (I_out) via a current-sense device (145).

29. The switched-mode power supply (100) as recited in Claim 21 wherein said controller (110) is further configured to provide a control signal (Csl , Cs2) to said at least one power switch (Ql, Q2) to regulate an output voltage (V_out) of said switched- mode power supply (100).

30. The switched-mode power supply (100) as recited in Claim 21 wherein said operating parameter of said switched-mode power supply (100) is selected from the group consisting of:

an output current (I_out) of said switched-mode power supply,

an output voltage (V_out) of said switched-mode power supply,

an output power (P_out) of said switched-mode power supply.