Abstract: A cellular phone (100) stores encrypted content data and encrypted license key distributed thereto in a memory card (110). The cellular phone (100) and the memory card (110) collectively perform a part of mutual authentication processing upon power-on. The encrypted license key (Kc) read from the memory card (110) is decrypted by a first decryption processing portion (1510) with a session key (Ks4), and is further decrypted by a second decryption processing portion (1514) with a system symmetric key (Kcom) for extraction. A third encryption processing portion (1516) decrypts the encrypted content data read from memory card (110) with the license key (Kc) to reproduce content data (Data).

Abstract: A ripple converter includes a transistor for switching an input direct-current voltage, a choke coil and a smoothing capacitor for smoothing the switched direct-current voltage, a flywheel diode for causing a current to flow through the choke coil when the transistor is turned off, and a comparing unit for controlling the ON/OFF of the transistor according to ripple in an output voltage. In the ripple converter, a waveform converter is provided on a connecting path between an output terminal and a non-inverting input terminal of a comparator in the comparing unit. A result of converting the waveform of the output voltage is compared with a reference voltage, and a result of the comparison is fed back to the transistor.

Abstract: Provided is a network system which is capable of smooth remote control of appliances in a household while improving the security. A household server for controlling home appliances and an external server for mediating between the household server and a user terminal are set on an Internet. The household server gives a right to access only to the external server that is registered in advance. When accessed by the user terminal, the external server performs user authentication and, if the access is authenticated as from an authorized user, specifies which household server is to be used by the user, and makes an access request to the corresponding server. The household server checks whether the access request is valid or not and, when the access request is found as a result to be valid, allows the user terminal to input a control instruction through the intermediation of the external server.

Abstract: Novel cellulose-producing bacteria including one capable of producing of a bacterial cellulose having a weight-average degree of polymerization in terms of polystyrene of 1.6×104 or above, one capable of producing a bacterial cellulose containing a small amount of the fraction with low degrees of polymerization, one producing a Bingham polysaccharide as a by-product, and one producing a small amount of water-soluble polysaccharide; a method for the production of bacterial cellulose, which comprises culturing these cellulose-producing bacteria; and bacterial cellulose thus obtained.

Abstract: A switching power source device includes a peak current limiting circuit in which peak current flowing through a first switching element is detected, and when the current reaches a predetermined value, transistors are turned on in succession to increase the quantity of an electrical signal whereby the first switching element is rapidly turned off, and an on-time limiting circuit for reducing the on-time using reduction of the output voltage. The switching power source device is operated so as to repeat starting and stopping due to a turn-on delay circuit when the output is shortcircuited for reduction of the shortcircuit current.

Abstract: A switching power supply unit includes a first switching control circuit, which has a first ON-time control circuit, and a second switching control circuit, which has a second ON-time control terminal. The first ON-time control circuit controls the ON-time of the first switching element such that, at light load, before a voltage generated across a first drive winding causes a first switching element to be turned on, a first control transistor is brought into conduction to prevent the first switching element from being turned on and to thereby stop oscillation. The second ON-time control circuit controls the ON-time of the second switching element such that, at light load, after the end of the ON-time of the second switching element, energy release from a secondary winding is completed.

Abstract: A switching power supply unit includes a transformer including a primary winding, a secondary winding, and a feedback winding; an input power supply and a first switching element that are connected in series with the primary winding; a control circuit provided between one end of the feedback winding and a control terminal of the first switching element; a rectification circuit connected to the secondary winding; and an output voltage detection circuit for detecting output voltage output from the rectification circuit and for sending a feedback signal to the control circuit. The control circuit includes an on-period control circuit for stabilizing the output voltage by turning off the first switching element in an on-state in accordance with the feedback signal. The control circuit also includes an off-period control circuit for stabilizing the output voltage by delaying turning on of the first switching element in accordance with the feedback signal.

Abstract: A self-excited oscillation type switching power source device is constructed such that when a power source switch is turned on, and the voltage of an input power source increases, the voltage at a point a is increased. When the voltage exceeds a predetermined voltage, a first transistor is turned on, and a second transistor is turned off. Then, a first switching element, when a starting voltage is applied to the control terminal thereof, is turned on, and voltage is developed in a first drive winding. This voltage is fed back to the point a via a feedback circuit. As a result, the transistor is accelerated to reach the on-state. The second transistor is accelerated to reach the off-state. As a result, the first switching element is rapidly turned on, and the oscillation is started.

Abstract: A memory card (110) includes a memory (1415) to store encrypted content data, a license hold unit (1440) to store at least a portion of license information distributed by a distribution system, a plurality of authentication data hold units (1400.1, 1400.2), each storing a plurality of authentication data that are authenticated respectively by a plurality of public authentication keys KPma, KPmb common to the distribution system, and a switch (SW2) to selectively provide the data from the plurality of authentication data hold units outside of said recording apparatus according to a request external to the memory card (110).

Abstract: A switching power supply unit includes first and second switching elements which are alternately turned on/off so as to perform self-excited oscillation. An inductor and a capacitor resonate during an OFF-period of the first switching element. After the second switching element is turned on, a resonance current applied to a series circuit including the second switching element and the indictor is interrupted before energy is completely emitted from a secondary winding. Accordingly, a voltage is generated at the inductor and a voltage at a transformer is reversed. The switching power supply unit also includes an ON-time control circuit in which a time constant is set so as to turn off the second switching element accordingly.

Abstract: A switching power supply apparatus comprises a transformer having primary winding and at least two secondary windings, a first switching element connected in series with the primary winding, a control circuit for controlling the output from the first switching element by control of the on-time thereof, a rectification circuit for rectifying at least two outputs from the secondary windings, an output detection circuit for detecting the output voltages and feeding back the output voltages as a control signal for control of the on-time to the control circuit. The output voltage detection circuit comprises a control signal formation section in which the control signal for the on-time is formed, corresponding to a voltage at a voltage comparison terminal, and plural voltage detectors connected between the at least two outputs of the secondary windings and the voltage comparison terminal, respectively.

Abstract: A switching power supply unit includes a control output circuit, a non-control output circuit, and a regulator circuit. With this switching power supply unit, it is no longer necessary to set the voltage of the non-control output to be greater than a required value when the control output circuit is unloaded or lightly loaded. The regulator circuit is connected to the non-control output circuit and includes a first transistor defining a first impedance element connected in series to the non-control output circuit, a second transistor defining a second impedance element connected between the control output circuit and the base of the first transistor, and a voltage control circuit controlling the impedance of the second transistor such that the output voltage of the regulator circuit is maintained constant.

Abstract: A switching power source device includes a peak current limiting circuit in which peak current flowing through a first switching element is detected, and when the current reaches a predetermined value, transistors are turned on in succession to increase the quantity of an electrical signal whereby the first switching element is rapidly turned off, and an on-time limiting circuit for reducing the on-time using reduction of the output voltage. The switching power source device is operated so as to repeat starting and stopping due to a turn-on delay circuit when the output is shortcircuited for reduction of the shortcircuit current.

Abstract: A switching power supply unit includes a first switching control circuit, which has a first ON-time control circuit, and a second switching control circuit, which has a second ON-time control terminal. The first ON-time control circuit controls the ON-time of the first switching element such that, at light load, before a voltage generated across a first drive winding causes a first switching element to be turned on, a first control transistor is brought into conduction to prevent the first switching element from being turned on and to thereby stop oscillation. The second ON-time control circuit controls the ON-time of the second switching element such that, at light load, after the end of the ON-time of the second switching element, energy release from a secondary winding is completed.

Abstract: A transformer including a first magnetic core and a second magnetic core having the shape of a flat plate. In the first magnetic core, a middle leg and substantially L-shaped outer legs whose inner sides are formed as circular-arc-shaped surfaces are provided in a standing manner at the central portion and at the comers of a rectangular flat plate, respectively. In addition, in the first magnetic core, a winding accommodating portion is formed between the circular-arc-shaped surfaces of the corresponding outer legs and an outer peripheral surface of the middle leg. Three coil portions, formed by spiral winding operations in level states, are placed upon each other, and are inserted into the winding accommodating portion of the first magnetic core. Then, from above the coil portions, the second magnetic core is placed thereon in order to form an integral structure.

Abstract: A switching power supply unit includes a control circuit including a turn-off circuit for turning of a first switch element Q1, which has been in an ON state, and an off-period control circuit for, based on a feedback signal from an output-voltage detecting circuit, controlling the turning-on of the first switch element to be further delayed as a load is lighter. The off-period control circuit includes a transistor as a second switch element which is provided in series between a feedback winding and the control terminal of the first switch element and which is controlled to be turned on and off based on the feedback signal from the output-voltage detecting circuit. A switching frequency is set to be lower as the load is lighter, such that power consumption at the light load is reduced.

Abstract: A transformer comprises first and second flat coils stacked with each other. Each of first and second flat coils comprises a conductive wire which is wound in a flat spiral shape having a through hole at a center thereof such that the conductive wire has an inner end and an outer end at an inner periphery and an outer periphery of the spiral shape, respectively. The inner end of the first flat coil passes through the through hole of the second flat coil, thus reducing the overall thickness of the transformer because both inner ends pass over only one flat coil.

Abstract: A switching power supply circuit including a transformer having a primary winding, a secondary winding, and a feedback winding; a direct-current power supply of which one end is connected to one end of said primary winding; a switching element connected in series between the other end of said direct-current power supply and the other end of said primary winding; a control circuit provided between the control terminal of said switching element and said feedback winding; a rectifying circuit connected to said secondary winding; and a constant-current circuit provided between the one end of said primary winding and the control circuit or the control terminal of said switching element.

Abstract: A switching power supply unit includes first and second switching elements which are alternately turned on/off so as to perform self-excited oscillation. An inductor and a capacitor resonate during an OFF-period of the first switching element. After the second switching element is turned on, a resonance current applied to a series circuit including the second switching element and the indictor is interrupted before energy is completely emitted from a secondary winding. Accordingly, a voltage is generated at the inductor and a voltage at a transformer is reversed. The switching power supply unit also includes an ON-time control circuit in which a time constant is set so as to turn off the second switching element accordingly.

Abstract: A switching power supply unit comprises: a transformer, a main switching element, a rectifying smoothing circuit, a mode switching circuit and a delay circuit. The transformer has a primary winding, a secondary winding and a bias winding. The main switching element is connected to the primary winding and receives an output of the bias winding as a positive feedback so as to form a ringing choke converter operating in self-excitation oscillation. The rectifying smoothing circuit is connected to the bias winding. The mode switching circuit is turned on and off depending on whether or not the rectifying smoothing voltage of the rectifying smoothing circuit is a threshold voltage or higher. The delay circuit is coupled to the mode switching circuit and is connected between the main switching element and the bias winding and delays the output of the bias winding and applies the delayed output to the main switching element.