摘要:
A low dropout (LDO) voltage regulator includes a voltage regulation loop for providing a gate drive signal to an output device, the gate drive signal proportional to an output current. The voltage regulation loop includes a current bias input for receiving a bias current. The LDO voltage regulator further includes a current bias control circuit for providing the adaptive bias current at a first value that is proportional to current limit value lab and the width-to-length ratio of transistors of the transconductance amplifier when the output current less than or equal to a threshold and increases the bias current from a threshold to a current limit value. The output current varies substantially linearly over a range of output current values between the threshold and the current limit value.
摘要:
In one embodiment, a voltage sense circuit receives an ac input signal and forms a rectified output voltage that is representative of the ac input signal.
摘要:
In one embodiment, a reference generator forms a reference signal that may have temperature and process variations. A comparator that has similar variations is used to detect a signal using the reference.
摘要:
In one embodiment, a voltage sense circuit receives an ac input signal and forms a rectified output voltage that is representative of the ac input signal.
摘要:
A band gap reference (32) provides low noise operation utilizing capacitor (98) to produce a low pass filter operating with high impedance node (104). Increased speed is realized using feedback signals at nodes (102) and (100) to control differential transistor pair (36, 42). A first current feedback stage using transistors (44, 50, 52 and 54) and a second current feedback stage using transistors (60, 62, 68, 70) is used to control current mirror stages which set the charge and discharge current at node (104). A first current mirror stage using transistors (64,76) comprise the current sink used to discharge capacitor (98) at node (104) and a second current mirror stage using transistors (58,74) comprise the current source used to charge capacitor (98) at node (104).
摘要:
In a bandgap reference circuit (200), a base-emitter voltage V.sub.BE with a first temperature coefficient TC.sub.1 is added to a voltage difference .DELTA.V with a second, opposite temperature coefficient TC.sub.2 by two resistors (210,220). The bandgap reference circuit (200) comprises current sources (271-276) and bipolar transistors Q(1) to Q(K) (281-286) of pnp-type and npn-type. Current densities in Q(1) to Q(6) are distributed so that some base-emitter voltages V.sub.BEk in Q(1) to Q(6) are different. The bases and emitters of Q(1) to Q(6) are serially coupled so that pn-junctions are arranged in a alternative directions, thus adding only the differences of V.sub.BEk but not adding their absolute values. This feature makes the circuit (200) applicable in a low voltage environment. The ratio between the two resistors (210,220) can have a value which minimizes noise voltages V.sub.N so that external filtering capacitors are not required.
摘要:
A band-gap voltage reference (39) has a regulator portion (70) providing a substantially constant current of predetermined magnitude Ic and a band-gap reference portion (72) receiving Ic. The reference portion (72) has a first branch including a first transistor (52) of a first type serially coupled to a second transistor (55) of a second type, a second branch including a third transistor (53) of the first type serially coupled to a fourth transistor (56) of the second type, the first and second branches forming a current mirror (73) carrying a total current of about Ic/2, and a third branch (57) in parallel with the first and second branches and carrying a current of substantially Ic-Ic/2. Base current (65) in the first two branches is compensated by base current (64) of the third branch.