摘要:
Ein erster Feldeffekttransistor (4) ist mit Drain und Source zwischen Kollektor und Basis eines bipolaren Transi stors (2) geschaltet. Durch eine entsprechende Steuerspan nung auf dem Gate (G) kann dieser FET (4) den bipolaren Transistor nahezu verlustlos ein- und ausschalten. Ein zwei ter Feldeffekttransistor (5) ist mit Drain und Source zwischen Basis und Emitter des bipolaren Transistors geschaltet und führt beim Sperren des bipolaren Transistors akkumulierte Ladungen rasch ab. Dadurch entsteht ein Schaltelement, das hohe Ströme bei niedrigen Steuerverlusten mit hoher Geschwindigkeit zu schalten ermöglicht.
摘要:
Schaltungsanordnung zur Minimierung der Wirkung parasitärer Transistorfunktionselemente (12) in integrierten bipolaren Halbleiterschaltkreisen (1) mit aktiven Transistor funktionselementen (11), bei der dem Eingang (4, 7) des aktiven Transistorfunktionselementes (11) eine pn-Diode (14, 15, 16) vorgeschaltet ist und bei der zwischen dem dem Eingang (4, 7) des aktiven Transistorfunktionselementes (12) abgewandten Anschluß der Vorschalt-pn-Diode (14, 15, 16) und dem Ausgang (3, 6) des aktiven Transistorfunktions elementes (11) eine pn-Diode (14, 15, 17) zur Vermeidung von dessen Sättigung liegt.
摘要:
A switching circuit comprises a switching transistor (26) having a base (28), an emitter (24) and a collector (34), a transformer (18) having a primary winding (20) and a secondary winding (22) one end (12) of which is coupled to the emitter and the other end (16) of which is coupled through a diode (30) to the collector. A resistor (36) is connected between the base and the emitter. The secondary winding (22) has a centre tap (14) connected to the base of the transistor. The diode (30) is arranged to conduct current into the collector and divert current available to the base emitter junction to prevent the collector base junction from being forward biased.
摘要:
Circuits for driving a switching transistor (T3) with a driver stage (T2, T4, T5, L1), as are used for example in horizontal deflection stages of television sets or computer monitors, are known in a wide variety of embodiments. The invention specifies a power-efficient and cost-effective circuit of this type which contains a comparator circuit (T1), which monitors the voltage (UC) across the current input of the switching transistor (T3) for the purpose of monitoring saturation by comparing said voltage with a reference voltage (UR), thereby effecting regulation. The comparator circuit may be realised, e.g. by a simple transistor circuit (T1), the reference voltage (UR) being applied to the control input of said transistor circuit, the current input of said transistor circuit being connected to the drive signal (US) of the driver stage, and the current output of said transistor circuit being connected to the voltage (UC) via the current input of the switching transistor (T3).
摘要:
A drive circuit for a high-speed integrated circuit, bipolar switching regulator is disclosed. The circuit runs at megahertz frequencies, yet is efficient as previously available bipolar integrated circuit switching regulators operating at much lower frequencies. The circuitry provides three switch drive currents: a first (nominal) current that is provided while the switch is off in order to conserve power; a second (boosted) current, provided while the switch is transitioning from off to on in order to increase the speed at which the switching element switches on; and a third (drive) current, provided after the switch has turned on for maintaining the switch at a desired point in saturation. The drive current, additionally, varies as a function of the load on the switch in order, again, to conserve power. Additional circuitry increases the speed at which the switch turns off, by momentarily boosting base discharge current during the on-to-off transition period of the switch. The circuitry also increases speed by enabling the drive current prior to switch turn on. The circuitry can regulate both positive and negative outputs using a common error amplifier, as well as providing a multifunction node for shutdown and synchronization. Additionally, the circuitry provides improved recovery from output overshoot conditions. An improved clamp, to prevent the switch from spending too much time in a high power state (which would slow the switch down), increases the stability of the switch as compared with previously known designs.
摘要:
A semiconductor integrated circuit includes a current source (1) for supplying a current i, a resistor (2), a switch (3) having a control end connected to the resistor (2), an output terminal (4) connected to the output end of the switch, a comparator (5) having a current path which is connected at one end to a connection node between the resistor (2) and the control end of the switch (3) and connected at the other end to the output terminal (4). The comparator (5) compares a voltage (i × R) occurring across the resistor (2) with a potential V of the output terminal (4) and permits the current i to flow into the output terminal (4) when the relation ( i × R ≧ V ) is attained.
摘要:
Die erfindungsgemäße Basisstromregelung dient insbesondere zur freien Einstellung des gewünschten Sättigungsgrades eines Leistungstransistors (T1) im eingeschalteten Zustand. Hierzu stellt eine parallel arbeitende Sättigungsgradregelung (SBR) durch Auswerten der mittels einer Ankoppeldiode (D2) abgegriffenen Spannung (U CET1 ) am Ausgang des Leistungstransistors eine Hilfsstellgröße (Δi BT1 ) im Kleinsignalbereich zur Verfügung. Diese wird bevorzugt dem Eingang eines Leistungsstellgliedes (LSG) in einer gesteuerten Treiberstufe (STS) zugeführt, welche die eigentliche Ansteuerenergie (SE) für den Basisstrom (I BT1 ) des Leistungstransistors (T1) bereitstellt.
摘要:
A high voltage bipolar transistor (TR1) is provided in a line deflection circuit comprising a diode (D), a retrace capacitor (CR), a trace capacitor (CT) and a deflection coil (Ly) connected as shown. The transistor (TR1) is controlled from a line oscillator (LO) whose pulse waveform is applied by way of a driver stage (DR) and a stage (AC) controlling the amplitude of the forward current for the base of the transistor (TR1). A signal representing the amplitude of the relative power in the transistor (TR1) is derived from a power sensor (PS) and applied to a power minimum detector (PM) whose output controls the amplitude control stage (AC) to set the transistor (TR1) for minimum power dissipation.