Patent Application
20130229161
This application claims priority to Taiwan Patent Application No. 101106728 filed on Mar. 1, 2012.
Not applicable.
1. Field of the Invention
The present invention relates to a modulating determination apparatus, a modulating determination method for use in a power supply circuit, and the power supply circuit. More particularly, the present invention relates to a power supply circuit having a plurality of modulating schemes, a modulating determination apparatus thereof, and a modulating determination method thereof.
2. Descriptions of the Related Art
Stable supply of electric power is an important factor for ensuring normal operations of various electronic circuits. In general electronic circuits, a regulator is disposed to supply a stable and reliable voltage level. However, different electronic circuits require different power supplies. In order to satisfy demands of different voltages in various electronic circuits, power supply integrated circuit (IC) manufacturers must design different kinds of regulators. For example, switching regulators and linear regulators are common ones, and among linear regulators, low dropout linear regulators have the simplest structures and are widely used.
Different regulators have to be coupled with different circuit components when being used. As an example, a switching regulator has to be coupled with an additional passive component (e.g., an inductor) when being used. In case no passive component is coupled in the circuit of the switching regulator or in case the passive component is broken due to factors such as dusts and moisture, the circuit becomes short-circuited. For this situation, a square-wave signal modulated by a switching circuit is presented directly at the output end, which cannot be used in the back-end circuits and may even damage components of the back-end circuits. As another example, when a low dropout linear regulator is used, no additional passive component is needed and, instead, it is connected in a short-circuited fashion for ensuring the voltage quality. If a passive component is coupled to the low dropout liner regulator, the low dropout linear regulator cannot operate efficiently.
Accordingly, there is an urgent need in the art to provide a technology that can detect a passive component conveniently to ensure normal operation of various electronic circuits (e.g., regulators).
The present invention provides a modulating determination apparatus and a modulating determination method for use in a power supply circuit, and the power supply circuit.
The modulating determination apparatus is for use in a power supply circuit, is configured to be coupled to an examined circuit, and comprises a driver circuit and a comparison circuit. The examined circuit has a first end and a second end. The driver circuit provides an impulse signal to the first end. The comparison circuit is coupled to the first end to obtain a first detected electric value of the first end, calculates a difference value between the first detected electric value and a second detected electric value, and produces a comparison result by comparing the difference value with a threshold value. The comparison result indicates whether the examined circuit comprises a passive component, which is used to decide to modulate the power supply circuit by either a first modulating scheme or a second modulating scheme so as to supply an output power.
The modulating determination method is for use in a power supply circuit and comprises the following steps of: (a) providing an impulse signal to an end of an examined circuit; (b) detecting the end to obtain a first detected electric value; (c) obtaining a second detected electric value; (d) calculating a difference value between the first detected electric value and the second detected electric value; (e) producing a comparison result by comparing the difference value with a threshold value, the comparison result indicating whether the examined circuit comprises a passive component; and (f) modulating the power supply circuit by either a first modulating scheme or a second modulating scheme according to the comparison result so as to supply an output power.
The power supply circuit comprises a pin, a driver circuit, a comparison circuit, a switching regulator, a low dropout linear regulator, and a selection circuit. The pin is to be coupled to an examined circuit. The driver circuit is coupled to the pin and for providing an impulse signal to the examined circuit. The comparison circuit is coupled to the first pin to obtain a first detected electric value and for producing a comparison result according to a difference value between the first detected electric value and a second detected electric value. The selection circuit decides to supply an output power by either the switching regulator or the low dropout linear regulator according to the comparison result.
The present invention determines whether an examined circuit comprises a passive component by obtaining two detected electric values of two ends of the examined circuit and then comparing a difference value between the two detected electric values with a threshold value. Therefore, the present invention can efficiently detect whether an examined circuit comprises a desired passive component. When this technology is applied to a power supply circuit, the power supply circuit can determine whether a passive component is coupled by a user so as to activate a proper circuit or output a proper signal.
The detailed technology and preferred embodiments implemented for the subject invention are described in the following paragraphs accompanying the appended drawings for people skilled in this field to well appreciate the features of the claimed invention.
In the following description, the principle of the present invention will be described in detail. In addition, the modulating determination apparatus and the modulating determination method for use in a power supply circuit as well as the power supply circuit based on the present invention will be explained with reference to various embodiments. However, these embodiments are not intended to limit the present invention to any environment, applications, or implementations described in these embodiments. Therefore, description of these embodiments is only for purpose of illustration rather than to limit the present invention. It shall be appreciated that, in the following embodiments and the attached drawings, elements not directly related to the present invention are omitted from depiction.
The impedance of a passive component is related with the frequency of an input signal. For example, the impedance of an inductor is directly proportional to the frequency of an impulse signal inputted. Hence, the higher the frequency of the impulse signal is, the larger the potential difference across the inductor will be. Such a characteristic of the inductor may also be reflected by other detected electric values, e.g. current values.
The driver circuit 11 provides the impulse signal 100 to the first end 151 of the examined circuit 15. Then, the comparison circuit 13 detects the first end 151 to obtain a first detected electric value and calculates a difference value between the first detected electric value and a second detected electric value of the second end 153. Since the output of the second end 153 is an expectable known value, the second detected electric value may be built in as a default value. Therefore, after detecting the first end 151, the comparison circuit 13 directly calculates the difference value between the first detected electric value and the built-in second detected electric value and then compares the difference value with a threshold value to output the comparison result 115. The comparison result 115 indicates whether the examined circuit 15 comprises a passive component. When the modulating determination apparatus 1 is used in a power supply circuit, modulating the power supply circuit by either a first modulating scheme or a second modulating scheme is decided according to whether a passive component exists so as to supply an output power.
In other embodiments, depending on the type and characteristics of the passive component and the type of the detected electric values, the comparison result 115 will present whether the examined circuit 15 comprises a passive component in different ways. For example, in case that the impedance of the passive component to be detected is positively correlated with the frequency of the impulse signal 100, the examined circuit 15 is determined to comprise the passive component if the comparison circuit learns that the difference value between the first detected electric value and the second detected electric value is greater than the threshold value. Continuing the same example, it is determined that the examined circuit 15 does to not comprise the passive component if the difference value between the first detected electric value and the second detected electric value is smaller than the threshold value.
The first detected electric value and the second detected electric value may be voltage values or current values. The passive component may be an inductor or a capacitor. In different embodiments, the present invention may be implemented by choosing different detected electric values according to the characteristics of the passive component to be measured.
In the second embodiment, the comparison circuit 23 is coupled to not only the first end 251 but also the second end 253 of the examined circuit 25. Therefore, when the driver circuit 21 provides an impulse signal 200 to the first end 251, the comparison circuit 23 can directly detect and obtain a first detected electric value of the first end 251 and a second detected electric value of the second end 253. The difference value between the first detected electric value and the second detected electric value is compared with a threshold value by the comparison circuit 23 to output the comparison result 215. The comparison result 215 indicates whether the examined circuit 25 comprises a passive component.
In actual circuits, the output level of the second end 253 of the examined circuit 25 is expectable. Considering the example that the modulating determination apparatus 2 is a power supply control IC and the examined circuit 25 is an output inductor and they form a switching regulator (SWR) together. In this case, regardless of whether the second end 253 is coupled to the comparison circuit 23, the difference value between the first detected electric value and the second detected electric value can be predicted through some techniques so as to determine the threshold value. In practical implementations, the input end for inputting the second detected electric value of the comparison circuit 23 may be designed to be grounded or directly coupled to some other node having a fixed voltage. In a preferred embodiment, the second detected electric value is a nonzero default value. As long as the difference value between the first detected electric value and the second detected electric value can exhibit the electric characteristic of the examined circuit 25 adequately and the threshold value is appropriately set, whether the examined circuit 25 comprises a passive component can be effectively determined It shall be noted that, if the comparison result 215 indicates that the examined circuit 25 has no inductive characteristic, it represents that the current circuit cannot be provided with a power by an SWR control approach. In this case, the output of the power supply must be turned off; or instead, the power is outputted by some other control approach that does not require existence of an inductor (e.g., the output is supplied to the second end 253 by a control approach using a low dropout linear regulator instead).
The third embodiment of the present invention is a modulating determination method, a flowchart diagram of which is depicted in
Firstly, step S301 is executed to provide an impulse signal to an end of an examined circuit. Next, step S303 is executed to detect the end of the examined circuit to obtain a first detected electric value. Then, step S305 is executed to obtain a second detected electric value. It shall be appreciated that, in other embodiments, step S305 may be executed before step S303 or steps S303 and S305 may be executed simultaneously.
Then, step S307 is executed to calculate a difference value between the first detected electric value and the second detected electric value. Step S309 is executed to compare the difference value with a threshold value to produce a comparison result, which indicates whether the examined circuit comprises a passive component. Finally, step S311 is executed to modulate the power supply circuit by either a first modulating scheme or a second modulating scheme according to the comparison result so as to supply an output power.
In this embodiment, the driver circuit 41 may be a p-channel metal-oxide-semiconductor field-effect transistor (PMOSFET). Additionally, the driver circuit 41, the comparison circuit 43, the switching regulator 47, the low dropout linear regulator 49, the D-type flip-flop 433, and the multiplexer 444 are all well known by those of ordinary skill in the art, and thus will not be further described herein.
As shown, when the end 402 of the examined circuit 45 is coupled to the pin 451, the driver circuit 41 provides the impulse signal 400 to the examined circuit 45 via the pin 451. The comparison circuit 43 also detects and obtains a first detected electric value of the end 402 via the pin 451, calculates a difference value between the first detected electric value and the second detected electric value Ref, and produces the comparison result 432 according to the difference value (e.g., by comparing the difference value with a threshold value).
The selection circuit 44 decides to supply an output power by either the switching regulator 47 or the low dropout linear regulator 49 according to the comparison result 432.
Specifically, the D-type flip-flop 433 is coupled to the comparison circuit 43, receives the comparison result 432 from the comparison circuit 43, and outputs the control signal 430 according to the comparison result 432. The multiplexer 444 is coupled to the switching regulator 47, the low dropout linear regulator 49, and the D-type flip-flop 433. According to the control signal 430, the first output signal 471 generated by the switching regulator 47 or the second output signal 491 generated by the low dropout linear regulator 49 is outputted by the multiplexer 444 to the pin 451 as the output power for output to the examined circuit 45.
When the power supply circuit 4 starts to provide the output power to the examined circuit 45, the driver circuit 41 stops providing the impulse signal 400 to the examined circuit 45. In other embodiments, the driver circuit 41 may be activated when connection of the examined circuit is detected (hot plugging detection) and then turned off after a preset time period, or may execute other commands from the system.
The end 602 of the examined circuit 65 is coupled to the power supply circuit 6 via the pin 651. In this embodiment, the driver circuit 61 may be a PMOSFET. The driver circuit 61 provides the impulse signal 600 to the pin 651. The comparison circuit 63 is coupled to the pin 651, obtains a first detected electric value from the pin 651, calculates a difference value between the first detected electric value and a preset second detected electric value Ref, and produces the comparison result 632 according to the difference value.
The selection circuit 66 decides to supply an output power by either the switching regulator 67 or the low dropout linear regulator 69 according to the comparison result 632. Specifically, the D-type flip-flop 62 is coupled to the comparison circuit 63 and outputs a control signal 633 according to the comparison result 632. The input end of the inverter 60 is coupled to the D-type flip-flop 62 and the inverter 60 generates an inverted signal EN-SWR according to the control signal 633. The enabling circuit 64 is coupled to the switching regulator 67, the low dropout linear regulator 69, and the inverter 60, receives the inverted signal EN-SWR from the inverter 60, and enables either the switching regulator 67 or the low dropout linear regulator 69 according to the inverted signal EN-SWR. The switching regulator 67 or the low dropout linear regulator 69 that is enabled then supplies the output power to the examined circuit 65 via the pin 651.
The power supply circuit 8 further comprises the selection circuit 88, the PMOSFET 845, the N-channel metal-oxide-semiconductor field-effect transistor (NMOSFET) 846, the switching regulation controller 87, and the low dropout linear regulation controller 89. The PMOSFET 845, the NMOSFET 846, and the switching regulation controller 87 can form a switching regulator; while the PMOSFET 845, the NMOSFET 846, and the low dropout linear regulation controller 89 can form a low dropout linear regulator. In other words, the switching regulator and the low dropout linear regulator of this embodiment have a common power stage.
The selection circuit 88 comprises the D-type flip-flop 62, the inverter 60, the AND gate 840, the error amplifier 842, and the transmission gates 843 and 844. The PMOSFET 845 has a source being coupled to a power supply (VDD) and a drain being coupled to a source of the NMOSFET 846. The drain of the NMOSFET 846 is grounded.
The first input end of the AND gate 840 receives the inverted signal EN-SWR, the second input end of the AND gate 840 is coupled to the switching regulation controller 87, and the output end of the AND gate 840 is coupled to the gate of the NMOSFET 846. The transmission gates 843 and 844 are coupled to each other. The first end of the transmission gate 843 is coupled to the switching regulation controller 87 and the second end of the transmission gate 843 is coupled to a gate of the PMOSFET 845. The transmission gates 843 and 844 have a negative inverted signal −EN-SWR therebetween. The error amplifier 842 has the input end coupled to the low dropout linear regulation controller 89 and the output end coupled to the first end of the transmission gate 844. The second end of the transmission gate 844 is coupled to the source of the PMOSFET 845.
When the inverted signal EN-SWR is at a high level, the output of the switching regulation controller 87 passes through the AND gate to turn on the NMOSFET 846. Furthermore, another output of the switching regulation controller 87 passes through the transmission gate 843 to turn on the PMOSFET 845. In this case, the switching regulation controller 87 generates the output signal Output as the output power for outputting to the examined circuit 65. It is learned that when the inverted signal EN-SWR is at the high level, the switching regulator formed by the PMOSFET 845, the NMOSFET 846, and the switching regulation controller 87 is activated.
When the inverted signal EN-SWR is at a low level, the output of the switching regulation controller 87 is unable to pass through the AND gate 840. Instead, the output of the low dropout linear regulation controller 89 controls the PMOSFET 845 and the NMOSFET 846. In this case, the low dropout linear regulation controller 89 generates an output signal Output as an output power for outputting to the examined circuit 65. It is learned that when the inverted signal EN-SWR is at the low level, the low dropout linear regulator formed by the PMOSFET 845, the NMOSFET 846, and the low dropout linear regulation controller 89 is activated.
According to the above embodiments, by virtue of the correlation between the impedance of a passive component and the frequency of an impulse signal, the present invention calculates a difference value between detected electric values of two ends of an examined circuit and then compares the difference value with a threshold value to produce a comparison result which indicates whether the examined circuit comprises a passive component. This technical feature can be further applied to a power supply circuit and implemented by various circuits. In this way, abnormal operations, short circuits, or burnout of the circuit can be avoided.
The above disclosure is related to the detailed technical contents and inventive features thereof. People skilled in this field may proceed with a variety of modifications and replacements based on the disclosures and suggestions of the invention as described without departing from the characteristics thereof. Nevertheless, although such modifications and replacements are not fully disclosed in the above descriptions, they have substantially been covered in the following claims as appended.
| Number | Date | Country | Kind |
|---|---|---|---|
| 101106728 | Mar 2012 | TW | national |
