摘要:
A DC-DC converter with an inductor connected in series with a power transistor between first and second terminals of a DC supply source, and with a modulator circuit that has a control output connected to a control gate of the power transistor. The modulator circuit provides a periodic pulse signal the duty cycle of which determines an output voltage at an output terminal of the converter. The modulator circuit comprises an oscillator that determines the frequency of the periodic pulse signal. The modulator circuit also comprises a feedforward structure that determines an approximated duty cycle for the pulse signal based on the value of the input voltage, the sensed output voltage and the amount of current flow in the inductor. An error amplifier in the modulator has a first input connected to a reference voltage source, a second input connected to the output terminal of the converter and an output that supplies a corrective signal used by the modulator to adjust the duty cycle of the pulse signal. Thus, a multiple path feedforward topology is proposed which delivers to the modulator information on input voltage, output voltage and switch current. The feedforward concept is complemented by a low gain error amplifier which compares the output voltage to the reference voltage, which is preferably internal.
摘要:
A switch mode power converter is provided which includes a switching cell with a supply input, an output and a control input. A summing comparator has first and second differential input pairs and an output. The output is connected to the control input of the switching cell. An oscillator provides a periodic waveform that is applied to a first one of the inputs of the first differential input pair of the summing comparator. An adjustable reference voltage source provides an adjustable reference voltage a predetermined fraction of which is applied to a second one of the inputs of the first differential input pair of the summing comparator. An error amplifier has differential outputs coupled to the second pair of differential inputs of the summing comparator and a differential input pair. A first input of the differential input pair is coupled to the output of the switching cell, and the adjustable reference voltage from the adjustable reference voltage source is applied to a second input of the differential input pair. Thus, the desired DC voltage is scaled to produce a DC reference for the comparator which generates the desired duty cycle for the pulse signal that drives the switching cell, and thus the desired regulated output voltage, with only minor corrections required across the error terminals to correct small parasitic terms.
摘要:
A DC/DC converter circuit including an inductance 10, two controllable switches 12, 14 and a controller 16 for controlling the switches 12, 14 is configured so that it is able to operate in two permanently alternating operating time phases. The switches 12, 14 in the DC/DC converter circuit are arranged so that when the controller 16 is in the first operating time phase it closes the first switch 12 and opens the second switch 14 in achieving a flow of energy from the input of the DC/DC converter circuit to the inductance 10 and then when the controller 16 is in the second operating time phase it opens the first switch 12 and closes the second switch 14 in achieving a flow of energy from the inductance 10 to the output of the DC/DC converter circuit. Prior to switching from one operating time phase into the other operating time phase an intermediate time phase is inserted for safety reasons, in which both switches 12, 14 of the DC/DC converter circuit are briefly opened.
摘要翻译:包括电感10,两个可控开关12,14和用于控制开关12,14的控制器16的DC / DC转换器电路被配置成能够在两个永久交替的工作时间阶段中操作。 DC / DC转换器电路中的开关12,14布置成使得当控制器16处于第一操作时间阶段时,其闭合第一开关12并打开第二开关14,以实现来自第一开关12的输入的能量流 DC / DC转换器电路到电感10,然后当控制器16处于第二操作时间阶段时,它打开第一开关12并闭合第二开关14,以实现从电感10到DC的输出的能量流 / DC转换电路。 在从一个工作时间阶段切换到另一个操作时间阶段之前,为了安全起见插入了中间时间相位,其中DC / DC转换器电路的两个开关12,14都被短暂地打开。
摘要:
A DC-DC converter with an inductor connected in series with a power transistor between first and second terminals of a DC supply source, and with a modulator circuit that has a control output connected to a control gate of the power transistor. The modulator circuit provides a periodic pulse signal the duty cycle of which determines an output voltage at an output terminal of the converter. The modulator circuit comprises an oscillator that determines the frequency of the periodic pulse signal. The modulator circuit also comprises a feedforward structure that determines an approximated duty cycle for the pulse signal based on the value of the input voltage, the sensed output voltage and the amount of current flow in the inductor. An error amplifier in the modulator has a first input connected to a reference voltage source, a second input connected to the output terminal of the converter and an output that supplies a corrective signal used by the modulator to adjust the duty cycle of the pulse signal. Thus, a multiple path feedforward topology is proposed which delivers to the modulator information on input voltage, output voltage and switch current. The feedforward concept is complemented by a low gain error amplifier which compares the output voltage to the reference voltage, which is preferably internal.
摘要:
A switch mode power converter is provided which includes a switching cell with a supply input, an output and a control input. A summing comparator has first and second differential input pairs and an output. The output is connected to the control input of the switching cell. An oscillator provides a periodic waveform that is applied to a first one of the inputs of the first differential input pair of the summing comparator. An adjustable reference voltage source provides an adjustable reference voltage a predetermined fraction of which is applied to a second one of the inputs of the first differential input pair of the summing comparator. An error amplifier has differential outputs coupled to the second pair of differential inputs of the summing comparator and a differential input pair. A first input of the differential input pair is coupled to the output of the switching cell, and the adjustable reference voltage from the adjustable reference voltage source is applied to a second input of the differential input pair. Thus, the desired DC voltage is scaled to produce a DC reference for the comparator which generates the desired duty cycle for the pulse signal that drives the switching cell, and thus the desired regulated output voltage, with only minor corrections required across the error terminals to correct small parasitic terms.
摘要:
The invention relates to an electronic device and a method for DC-DC conversion using a comparator for generating an output signal for driving a power switch of a switch mode DC-DC converter. The electronic device is configured to reduce a bias current of the comparator with a first slope in response to a decreasing load and to increase the bias current of the comparator with a second slope in response to an increasing load, wherein the second slope is steeper than the first slope.
摘要:
A CMOS circuit (10), which is integrated in a semiconductor substrate, comprises a principal circuit part (12), which includes the major part of the circuit components in a well isolated from the substrate by a substrate diode. The CMOS circuit furthermore comprises a power output stage (16) driving an inductive load (26, 28). A sensor (18) is connected with one output (22, 24) of the power output stage (16) and on detection of a voltage biasing the substrate diode (30, 32) in the conducting direction produces a switching signal at the output. On occurrence of the switching signal produced by the sensor (18) a controllable switch (20) disconnects the supply voltage from the principal circuit part (12). In its own separate well (46) a status memory (14) is formed on the substrate adjacent to the principal circuit part (12), such status memory (14) comprising memory elements for storage of status data of the principal circuit part (12) on disconnection of the supply voltage.
摘要:
A converter has a main feedback path and two auxiliary feedback paths from an output node to an auxiliary differential input pair of a comparator. The auxiliary feedback paths have different RC time constants so that a differential ramp signal is effectively applied to the auxiliary differential inputs of the comparator. The circuit design compensates for a negligibly small equivalent series resistor of an output capacitor so that modern capacitors may be used without compromising the stable oscillation of the converter.
摘要:
An integrated circuit including a precharge circuit for a DC/DC boost converter which includes a reference current circuit with a MOSFET transistor (MP4) that has a gate connected with the gate of the DC/DC boost converter's power MOSFET transistor (MP5) to form a current mirror. The precharge circuit works to approach the output voltage to the supply voltage prior to the converter startup. An included regulation circuit adjusts the gate potential at the power MOSFET transistor (MP5) and at the MOSFET transistor (MP4) in the reference circuit in response to a reduction of the drain-source voltage of the power MOSFET transistor (MP5) due to precharging load capacitance, in a sense to keep the precharge current through the power MOSFET transistor (MP5) constant.
摘要:
In the proposed method of generating a pulsed output signal from a periodic ramp signal and a reference voltage, the linear range of duty cycles of the pulsed output signal is significantly extended to minimum values. The ramp signal and the reference voltage are applied to inputs of a comparator and the output signal is taken from an output of the comparator. The ramp signal has a ramp that extends between a minimum voltage level and a maximum voltage level. The duty cycle of the pulse signal is controlled by varying the reference voltage between the minimum and maximum voltage levels. The ramp has an initial start section extending from the minimum voltage level and a main section extending between the initial section and the maximum voltage level. The ramp slope has a constant value over the main ramp section and a value greater than the constant value over the initial section. In the initial section of the ramp the slope is varied in a manner to compensate for non-linearity of the comparator in an operating range where the reference voltage is close to the minimum voltage level of the ramp signal. It is also preferred to insert a short blanking period before the actual ramp of the waveform. The method can be used in switched mode power converters and in class-d amplifiers.