ITBO20110527A1 - VERY LOW CONSUMPTION CIRCUIT WITH ABSOLUTE VALUE SUITABLE FOR USE IN AN EXTENDED TEMPERATURE FIELD - Google Patents

Description

"LOW CONSUMPTION CIRCUIT VALUE RECTIFIER

ABSOLUTE SUITABLE FOR USE IN A FIELD OF

EXTENDED TEMPERATURE "

patent for industrial invention

STATE OF THE ART

Many technical solutions are known which use semiconductor diodes to realize rectifier circuits without a specific power supply system and in which an output signal is produced which approximates the absolute value of a time-varying input signal.

In box PA-01 of Figure 2 (prior art) a solution is shown, without a specific power supply system, which uses 4 diodes (2a, 2b, 2c and 2d) connected in bridge so as to rectify the positive half-waves 5a and 5b of a signal injected between terminals la and lb to produce a signal composed of positive half-waves 6 which reproduce the half-waves of the input signal both positive 5a and negative 5b but with a reduction 7 of the peak voltage due to the voltage drop of the directly biased diodes.

In box PA-02 of Figure 2 (prior art) a further solution is shown, without a specific power supply system, in which the input signal is applied to the primary 21 of a transformer 22 equipped with a secondary with a central socket connected to the ground 32 and whose half-windings 24 and 25 are connected to the output terminal 31a through two diodes 29 and 30 in such a way as to produce a signal composed of only positive half-waves 34 which reproduce the half-waves of the input signal both positive 33a and negative 33b but with a 35 reduction of the peak voltage due to the voltage drop of the directly biased diodes.

Due to the voltage drop of the directly biased diodes, the known technical solutions attributable to or similar to those mentioned are not suitable for use in situations where said drop introduces intolerable losses for the purposes of the energy efficiency of the system or its operation, or introduces an error between the rectified value produced and the real absolute value of the input signal which is not tolerable.

Numerous technical solutions are also known which use active amplification and / or switching systems in order to produce a signal equal to the absolute value of the input signal.

Among others, the documents CN 1080413 (Chen Y., 1994), CN 2739705 (Wang Y., 2005), JP 5199760 (Wakamatsu H. and Kitazawa M., 1993), JP 6197018 (Yasunaga S., 1994), JP 55163461 (Sato H, 1980), JP 58146863 (Tsuchiya T., 1983), JP 58225358 (Sato H, and Sakano R., 1983), JP 59116878 (Sasaki H., 1984), JP 59165566 (kill W., 1984), JP 60033671 (Matsuzawa A. and Inoue M., 1985), JP 60218174 and JP 60218175 (Arai Y. and Hagiwara S., 1985), JP 61046566 (Hayakawa M. and Suzuki N., 1986) , JP 61075480 (Sensou H. and Yoshida M., 1986), JP 62026585, JP 62122403 and JP 62117085 (Hayakawa M., 1987), JP 63128488 (Sato H. and Kitagami S., 1988), JP 2001016040 (Hanaoka T . and Shirasho J. H., 2001), JP 2007020307 (Ikeda K., 2007), KR 200156144 (Choi J., 1999), EP 0520432 (Furukawa T., 1992), JP 1095376 (Tsukiyama Y, 1989), JP 2135579 ( Nakao K. and Sato H., 1990), JP 2895036 (Azetsuji M., 1999), JP 3010410 (Nishimura K., 1991), JP 7046845 (Komiya H., 1995), JP 7210616, JP 7220013 and JP 72121 34 (Awatari K., 1995), JP 8043455 (Yamamoto S., 1996), JP 8078963 (Awatari K., 1996), JP 10048265 (Nagaya M., 1998), JP 10257771 (Kaneko S., 1998), JP 11064394 (Kimura H., 1999), JP 52014332 (Kanehara T, et al., 1977), JP 52017744 (Tacheuchi Y., 1977), JP 53108353 (Hanaoka S. et al., 1978), JP 55049977 (Kiwaki H . and Yamazaki M., 1980), JP 55105415 (Kikuchi H., 1980), JP 56033765 (Itou H, 1981), JP 56050468 (Marita M., 1981), JP 56159764 (Rumano T., 1981), JP 57172473 (Kazeto H, 1982), JP 57206984 (Yshigachi Y, 1982), JP 58069467 (Sato H, and Sakano M., 1983), JP 59081562 (Maeda K., 1984), JP 61029975 (Izawa Y., 1986), JP 63085368 (Nagano K., 1988), US 3882327 (Brown A., Schlesier K. M., 1975), US 3989997 (Ahmed Adel Abdel A., 1976), US 4461961 (kendall L., 1984), US 5394107 (Shou G . et al., 1995), US 5642070 (Furukawa T., 1997), US 5703518 (Yamamoto S., 1997), US 5751779 (Weir M. P., 1998), US 6724233 (Wittlinger H. A., 2004) which describe ideal rectifiers made with the impie g of switching elements and / or amplifiers and / or diodes that require a specific power source.

Box PA-03 of Figure 2 (prior art) illustrates the basic operating principle to which a part of the known documents referred to can be traced, in which an active system 12 controls the status of a switching system 11 based on the phase of the signal by rectifying so that the output signal consists of only positive half-waves 15 taken respectively without inverting the positive half-waves 14a of the input signal and inverting the negative half-waves 14b of the same.

In box PA-04 of Figure 2 (prior art) a further known type of ideal rectifier circuit is illustrated, to which a part of the known documents cited can be traced and in which the circuit is implemented by means of differential amplifiers (62a, 62b), diodes (63a , 63b) and other feedback elements (64a / b / c / d / e) and connected so as to use the rectifying function of the diodes while compensating for the relative voltage loss in forward bias.

The known ideal rectifier solutions mentioned above are characterized by a relative level of circuit complexity and by the need for a specific power supply for the active systems that they include and for this reason, even if this power supply can be derived from the same signal by rectifying at the input, they are not suitable for use in situations where the peak amplitude of the rectifying signal is extremely low and / or when it is necessary to particularly reduce energy consumption.

Also known are the documents WO 9628879 (Scheelen J., 1996), US 4819147 (Bingham D., 1989) and JP 63064572 (Okutsu K. et al., 1988) which describe technical solutions where the rectification is carried out by means of 4 or more transistors connected in such a way as to ensure active rectification and the production of the control signals which command said active rectification. These solutions are characterized by a relative level of circuit complexity and do not include specific devices that allow their efficient operation, especially in situations where the peak amplitude of the rectifying signal is extremely low.

Finally, document EP 2348606 (Jogia P., 2011) is known, which suggests to realize rectifiers without voltage loss in direct bias using MOSFETs characterized by a nominally null value for the threshold voltage which, applied between "gate" and " source "brings the transistor into saturation, such as the" n "channel MOSFETs of the" zero threshold "type" Electrically Programmable Analog Device "produced by the company" Advanced Linear Devices, Ine. " (IT CAUSES).

In box PA-05 of Figure 2 (prior art) the solution suggested by EP 2348606 is illustrated, in which "source" and "gate" of MOSFET 71 are connected together. The cited solution could be used to realize a type of rectifier already known, such as for example those indicated in boxes PA-01 and PA-02 of Figure 2 (prior art). Since the above-mentioned MOSFETs are characterized by a drift 77 of the value of the effective saturation threshold voltage as the temperature varies, when the temperature moves away from the zero point of the threshold voltage, said types are characterized by a distortion 78 of the rectified half-waves 75 in the interval in which the MOSFET is turned on in linear regime, since the voltage has not yet reached the real saturation threshold.

D E S C R I Z I O N E D E L L 'I N V E N Z I O N E

The main purpose of the present invention is to provide an extended absolute value rectifier circuit which is:

suitable to be used also in situations where the peak amplitude of the rectifying signal is extremely low, and,

do not foresee the need for a specific diet, e

suitable for use also in situations where it is necessary to reduce energy consumption in a particular way, e

characterized by a higher level of circuit simplicity than known solutions, e

capable of operating in an extended range of operating temperatures with a negligible variation in its performance.

The present invention will now be described with reference to the attached figures which include its non-limiting embodiments.

Figure 1 illustrates a preferred embodiment of the present invention in which the main components of the system are illustrated within box 40.

The input signal 43 is applied to the terminals 41a and 41b and reaches the winding 44 of the transformer by inducing an electro-motive force (EMF) in each of the windings 47, 48, 49 and 50 which are magnetically coupled to the winding 44 through the ferromagnetic core 46 of the transformer 45; called f.e.m. induced in each winding has an amplitude correlated to the ratio between the number of turns between the winding in question and the primary winding 44, and a phase imposed by the direction indicated for the winding in question with respect to the primary winding 44. Having the windings 47 and 49 a number of turns greater than those of the windings 48 and 50 respectively, they are characterized by a greater amplitude of the relative f.e.m ..

In particular in the winding 47 which has one end connected to the mass 58, an emf is induced. with half-waves 51a and 51b, in phase with respect to signal 43, which is applied to the "gate" terminal of a device 53 consisting of an "Electrically Programmable Analog Device - n-channel MOSFET with zero saturation threshold voltage" of the type those produced by Advanced Linear Devices Ine. (CA, USA), while the "source" and "drain" terminals of the device 53 are respectively connected to ground and to the end of the winding 48 in counterphase with respect to the signal 43. In this configuration the device 53 goes into saturation for the entire duration of the positive half-wave 51a by opening a path with negligible impedance between the ground 58 and the end of the winding 48 connected to the "drain", a condition that allows the positive half-wave 52b of the signal on the opposite end of the winding 48, to form the half-wave 59a of the rectified signal referred to the ground 58. For the entire duration of the negative half-wave 51b the device 53 is instead in interdiction, preventing any electric current from flowing in the winding 48.

Similarly, in the winding 49 which has one end connected to the ground 58, an emf is induced. with half-waves 54a and 54b, in phase opposition with respect to the signal 43, which is applied to the "gate" terminal of a device 56 similar to the device 53 already mentioned, while the "source" and "drain" terminals of the device 56 are respectively connected to ground and to the end of the winding 50 in counterphase with respect to the signal 43. In this configuration the device 56 goes into saturation for the entire duration of the positive half-wave 54b, opening a path with negligible impedance between the mass 58 and the end of the winding 50 connected to the "drain", a condition that allows the positive half-wave 55b of the signal on the opposite end of the winding 50 to be taken at point 57, to form the half-wave 59b of the rectified signal referred to ground 58. For the entire duration of the negative half wave 54a the device 56 is instead in interdiction, preventing any electric current from flowing in the winding 50.

The illustrated circuit therefore allows to collect only positive half-waves 59a and 59b at the ends of the resistive load 42, not necessarily forming part of the device itself, connected between the output terminal 57 and ground.

The solution described is also characterized by the fact that the saturation condition in the MOSFETs 53 and 56 is controlled by a signal 86 applied to the relative "gates" having a peak amplitude greater than that of the rectifying signal 80, a condition that reduces the time interval 87 between the crossing of the zero point and the reaching of the effective saturation voltage between the "gate" and the "source", an interval during which the linear ignition regime of the MOSFETs can induce a distortion 90 of the rectified signal 89.

In the solution described, said distortion 90 can therefore be reduced to a negligible level with respect to the distortion 84 which would occur if the peak amplitude of the control voltage applied between "gate" and "source" was equal to that of the signal by rectifying 80 even when the temperature conditions impose an effective non-zero value of the saturation voltage of MOSFETs 53 and 56.

Furthermore, the illustrated solution does not require any specific power supply apart from a negligible fraction of power subtracted from the pilot signal 43.

Figure 3 illustrates an alternative embodiment of the circuit of the present invention, in which the rectifying signals 110a / b and 116a / b are collected at the opposite phase ends of two secondary windings 106 and 108 having a common end and connected to ground 118, and in which the MOSFETs 111 and 117, of the same type as those described for the elements 53 and 56, each collect on their own "source" one of the rectifying signals 110a / b and 116a / b and are respectively switched on by the positive half-wave 109a and 115a of the control signals 109a / b and 115a / b in turn induced in the windings 105 and 107 which have more turns than the windings 106 and 108 and which each refer to the "source" of its own controlled MOSFET 111 and 112.

The rectified signal is then collected at the "drains" of the MOSFETs 111 and 117 which are short-circuited to each other.

Figure 4 illustrates a further alternative embodiment of the circuit of the present invention, in which "p" channel MOSFETs 130 and 134 with low saturation threshold voltage of the type produced by Advanced Linear Devices Ine are used. (IT CAUSES).

The operation of the circuit of Figure 4 is conceptually similar to that of Figure 3, with the peculiarity that the connection of the windings 125 and 128 is such as to generate control signals 129a / b and 132a / b in phase opposition with respect to the relative rectifying signals 131a / b and 135a / b so that the ignition of the MOSFETs 130 and 134 is correctly controlled only in conjunction with the positive half-waves 131a and 135a of the rectifying signal.

Figure 5 illustrates a further alternative embodiment of the circuit of the present invention, according to a scheme which is similar to the circuit illustrated in Figure 1 but having the peculiarity of using a transformer 147 of the piezoelectric type instead of magnetic induction.

In the circuit of Figure 5, the input signal 141 is applied between one or more pairs of electrodes 142a, 142c and 142b, 142d arranged on faces of a piezoelectric element 148a / b formed in such a way as to ensure a coupling between mechanical deformation and displacement of charges electric. Following the variation of the electric potential difference induced on these faces by the input signal 141, the piezoelectric element is brought from an initial undeformed configuration 148a to a deformed configuration 148b dependent on the potential applied and variable with it. Said variation in deformation undergone by the element is in turn responsible for producing a variation in potential 152a / b and 153a / b between other pairs of electrodes 143a, 143c and 143b, 143d and 144a, 144c and 144b, 144d present on the aforementioned faces of element 148a / b.

The mechanical deformation along the axis 149 is also responsible for a deformation by pinching along a different axis 150 of the piezoelectric element, a deformation which is linked to the production of a variation in potential between pairs of electrodes 145a, 145b and 146a, 146b suitably arranged , potential variation whose peak amplitude can be amplified with respect to that of signals 141, 152a / b and 153a / b with a suitable arrangement of the electrodes.

The piezoelectric transformer thus described is therefore capable of generating pairs of rectifying signals 152a / b and 153a / b with opposite phase when the electrodes 143a, 143c and 143b, 143d and 144a, 144c and 144b, 144d are suitably connected, and can also generate pairs of control signals 151a / b and 155a / b characterized by an amplified peak amplitude with respect to the rectifying signals and having opposite phase when the electrodes 145a, 145b and 146a, 146b are suitably connected.

Said rectifying and control signals can therefore be used in a circuit comprising at least two MOSFETs of the type already mentioned in order to produce a rectified waveform 159a / b with the advantages and characteristics already described.

Finally, it is clear that modifications and variations can be made to the described device without however departing from the scope of protection of the present invention.

Claims (7)

"LOW CONSUMPTION DEVICE FOR LONG-TERM CONTINUOUS MONITORING OF THE ACOUSTIC EMISSION WITH RECORDING OF PECULIARY PARAMETERS TO IT CONCERNING" R I V E N D I C A Z I O N I 1. An apparatus for rectifying a time-varying electrical input signal (43) in order to obtain its absolute value instant by instant, said apparatus being characterized by the fact that: it can work correctly even when the amplitude of the input signal is extremely small, e it does not require a specific power supply in addition to a negligible amount of power which is absorbed in a parasitic way by the same input signal, and it can be used in systems that have the specific need to reduce energy consumption and increase efficiency, and requires a number of transistor devices lower than that of other known systems, and can operate in an extended temperature range with a variation of the distortion of the output signal lower than that obtainable under the same conditions with other known systems, and said apparatus being characterized in that it comprises: at least one transformer (45), or a plurality of transformers, connected so as to be excited by the input signal (43) and to produce at least two distinct rectifying signals (52a / b and 55a / b) with equal amplitude and opposite phase the with respect to each other, and to produce at least two distinct control signals (51a / b and 54a / b) with opposite phase to each other and both having amplified peak amplitude with respect to that of the rectifying signals (52a / b and 55a / b); And at least two transistors (53, 56) connected in such a way as to allow the circulation of current each in a different path of the rectifying signals (52a / b and 55a / b) and only when the aforementioned transistors (53, 56) are alternatively controlled in the condition of switching on from the half-waves of only one type of one of the control signals (51a / b and 54a / b); and in which the aforesaid transformer (45) and transistor (53, 56) are connected together with the ground (58) and output (57) terminals according to a scheme characterized by the fact that the direction of flow of the current circulation which is alternatively admitted in the different paths of the rectifying signals (52a / b and 55a / b) is associated with the production between ground (58) and output terminal (57) of a voltage signal composed of only half-waves (59a, 59b) which have the same polarity . 2. An apparatus according to claim 1 characterized by the fact that at least one of the aforementioned transistors (53, 56) is a device characterized by a null or negligible value for the threshold voltage which, applied between "gate" and "source" carries the transistor in saturation. 3. An apparatus according to claim 2 characterized in that at least one of the cited transistors is an "n" channel MOSFET of the "zero threshold" type "Electrically Programmatile Analog Device" such as those produced by the company "Advanced Linear Devices, Inc." (IT CAUSES). 4. An apparatus according to any one of claims 1, 2 or 3 which comprises at least one system for limiting the peak value of the control signals (51a / b and 54a / b) to a maximum value preventing the possibility that the mentioned transistors (53 , 56) can be damaged. 5. An apparatus according to any one of claims 1, 2, 3 or 4 characterized in that it comprises a transformer (45) with a primary winding (44) driven by the input signal (43) and having four windings or secondary winding parts coupled to the primary winding (44) by magnetic induction; and wherein the first secondary winding (47) and the second secondary winding (48) both have the same winding direction as the primary winding (44); and in which the first secondary (47) is connected so as to produce a signal referred to ground (58) in phase with the pilot signal (43), and this signal is applied to the "gate" of a first "n-channel MOSFET "(53) having" source "connected to ground and" drain "connected to one end of the second secondary winding (48) such that current circulation is allowed only in the sense associated with the presence of a positive voltage at the opposite end of the same winding when the aforesaid MOSFET is kept in saturation by the signal which is applied to its own "gate" during a single half-cycle of the pilot signal (43); and wherein the transformer (45) has a third (49) and a fourth (50) secondary windings both having opposite winding direction to that of the first secondary winding (47); and the third secondary (49) connected so as to generate an inverted signal referred to ground (58) with phase opposite to that of the pilot signal (43), and this inverted signal is applied to the "gate" of a second MOSFET (56 ) of the same type as that of the first MOSFET (53) and having "source" connected to ground (58) and "drain" connected to one end of the fourth secondary winding (50) such that current circulation is allowed only in the direction associated with a positive voltage at the opposite end of the same winding when the second MOSFET (56) is brought into saturation by the signal applied to its "gate" during the second half-cycle of the pilot signal (43); and the rectified signal is made available at the output terminal (57) which connects together the ends of the second and fourth secondary (48, 50) to which the aforementioned positive voltages are induced. 6. An apparatus according to any one of claims 1, 2,3 4 or 5 characterized in that the transformer (45) comprises a plurality of winding coils (44, 47, 48, 49, 50) coupled together by magnetic induction . 7. An apparatus according to any one of claims 1, 2,3 4 or 5 characterized in that the transformer (147) comprises a plurality of electrodes (142a / b / c / d, 143a / b / c / d, 144a / b / c / d, 145a / b and 146a / b) coupled to at least one piezoelectric element (148a / b) according to a configuration which forms at least one piezoelectric transformer.