摘要:
The communication bus system comprises a plurality of node circuits (10a-d) and a relay circuit (12, 14, 16) coupling the node circuits (10a-d). The relay circuit (12, 14, 16) has a transceiver circuit (124, 164) for relaying messages (21) between the node circuits (10a-d) in a normal mode. The transceiver circuit (124, 164) is powered down in a sleep mode. A detector circuit (120, 160) detects an incoming message (41) when the relay circuit (12, 14, 16) is in a sleep mode. A mode control circuit (122, 162) powers up the transceiver (124, 164) in response to detection of an incoming message (21). Steps are taken that ensure, in the normal mode, that messages (21) will not be relayed in unreadable form. The mode control circuit (122, 162) is arranged to cause the transceiver (124, 164) to relay a remainder (25) of the incoming message (21) after power up. In an embodiment the power needed to transmit the remainder (25) of the message (21) is drained from a capacitor (306) in the power supply (30) before the power supply (30) controls the power supply voltage in the normal mode. In another embodiment the detector circuit (120, 160) temporarily controls the direction of operation of the transceivers (124, 164) at the start of the normal mode instead of further detectors (58a-d) that normally control the direction of operation in the normal mode.
摘要:
Line driver for a LIN-bus. The line driver has a current source output transistor (T1) for pulling down the LIN-bus wire (LB) to ground (GND). The LIN-bus wire (LB) is connected to a positive supply voltage (VBAT) through a pull-up resistor (R1). The output transistor (T1) provides a ramp shaped output current under control of a ramp generator (RG). The ramp shaped output current in combination with the pull-up resistor (R1) asserts a ramp shaped output voltage on the LIN-bus wire (LB). According to the LIN-bus specifications the resistance of the pull-up resistor may vary between 500 Ohm and 1 kOhm. When the resistance is 1 kOhm, the output voltage is clamped to signal ground (GND) and a delay occurs between the edge in the data signal (TXD) and the corresponding rising ramp in the output voltage. This delay is reduced considerably by a comparator (CMP, T2) which monitors the output voltage and which increases the slew rate of the ramp generator (RG) when the output voltage is clamped and drops below a certain threshold.
摘要:
A ballast circuit for operating a lamp provided with a voltage-current converter, the ballast circuit having a differential amplifier provided with a first input terminal for connection to a reference voltage source for generating a reference voltage, a second input terminal for connection of a reference resistor, and an output. A first current generator supplies a first current to the reference resistor. A current amplifier generates a second current and is provided with an input coupled to the output of the differential amplifier. The differential amplifier is provided with a low-pass filter. The current amplifier on the one hand and the current generator and the reference resistor on the other hand exclusively comprise mutually separate components. The ballast circuit is in addition provided with a current control circuit coupled to the current amplifier and to the current generator for influencing the first current dependent upon the second current. As a result, an interference signal present at the second input terminal causes no appreciable interference in the second current.
摘要:
An electronic circuit having first (VSS) and second (VDD) power supply terminals and comprising a first digital driver (DRV) and a further digital driver (DRVF). The digital drivers (DRV, DRVF) are arranged for driving capacitive loads such as charge pump capacitors (CP1, CP2) of a charge pump (CHGP). The first digital driver (DRV) comprises a first field effect transistor (T1) having a source coupled to the first power supply terminal (VSS), a drain coupled for driving the first charge pump capacitor (CP1), and a gate; a second field effect transistor (T2) having a source coupled to the second power supply terminal (VDD), a drain coupled to the drain of the first field effect transistor (T1), and a gate; a first capacitor (C1) coupled between the gate of the first field effect transistor (T1) and an input terminal (CLK) for receiving a digital input signal (UCLK); and a second capacitor (C2) coupled between the gate of the second field effect transistor (T2) and the input terminal (CLK). The further digital driver (DRVF) is constructed in a similar way as the digital driver (DRV). DC paths are formed between the gates of field effect transistors (T1-T4) and the supply terminals (VSS, VDD). Owing to the special construction of the digital drivers (DRV, DRVF), there is never a short-circuit current between the digital drivers (DRV, DRVF). As a result, the digital drivers (DRV, DRVF) have a very high power efficiency.
摘要:
In a transmission system a transmitter (12) is coupled to a receiver (13) via a transmission line comprising two wires (1,2). The transmitter (12) generates on said wires two voltages with respect to a reference voltage being opposite in phase. To enable the transmission system to operate in case of a short circuit between the wires (1,2), said two voltages are generated by sources having different short circuit currents.
摘要:
An amplifier arrangement includes a first amplifier (A1) having a first output terminal (5) for the connection of a first terminal of a load and having at least a first power transistor (PT1) with a main current path for carrying a first current (i1), which current (i1) is related to a first load current flowing via the first output terminal (5), a second amplifier (A2) having a second output terminal (6) for the connection of a second terminal of the load and having at least a second power transistor (PT2) with a main current path for carrying a second current (i2), which current (i2) is related to a second load current flowing via the second output terminal (6) a first circuit (M1) for generating a first signal (s1), which signal (s1) is related to the first current (i1), a second circuit (M2) for generating a second signal (s2), which signal (s2) is related to the second current (i2), a third circuit (M3) for generating at least one control signal (r1, r2), which control signal (r1, r2) is related to a sum of the first (s1) and the second (s2) signal, and a protection circuit for limiting the first and the second load current depending upon the control signal (r1, r2), the third circuit (M3), in addition to being adapted to generate the control signal (r1, r2), being adapted to supply a first short-circuit current (k1) to one of the output terminals (5, 6) during a first short-circuit mode and to supply a second short-circuit current (k2) to one of the output terminal (5, 6) during a second short-circuit mode, which short-circuit currents (k1, k2) are related to the sum of the first (s1) and the second (s2) signal.
摘要:
An apparatus for monitoring the current in an integrated circuit provided with a current conductor which is to supply current to a semiconductor structure at least temporarily and to supply current to other parts of the circuit. The current conductor is locally split into a first and a second parallel partial current conductor, with the semiconductor structure connected to the first partial current conductor. The first and second partial current conductors are connected to respective first and second connection contacts across which a voltage drop can be derived which is a measure of the value of the current flowing through the semiconductor structure.
摘要:
An input signal (Vin) is applied to a first amplifier (A1) and a second amplifier (A2) via a circuit (M), which amplifiers are both coupled to an output terminal (U) to supply an output voltage (Vuit). For this purpose the circuit (M) generates two mutually complementary signals which are related to the output signal (Vuit) and the maximum signal values corresponding to the individual output signals of the first amplifier (A1) and the second amplifier (A2). The output signal to be supplied (Vuit) consequently dictates which amplifier (A1, A2) is driven into full conduction.