Convertidor Cúk. L1 L2 C1. V1 uH 10u mH C2 R1 u. V3 D1 MUR TD = 0. V2 = PW = 45u. PER = 50u. V1 = 0. 0. Voltaje Inductor. A partir del modelo de tiempo continuo del convertidor, se obtiene el modelo . of a bidirectional coupled –inductor Cuk converter operating in sliding-mode. Cuk Converter. 0. Favorite. 4. Copy. Views. Open Circuit. Cuk Converter. Social Share. Circuit Description. Graph image for Cuk Converter. Circuit Graph.
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However, engineers often unknowingly refer to these topologies by the wrong name, adding confusion to an area that already is a bit confusing. What does each topology do?
Why choose one topology over the other? The reasons vary, with some being more obvious than others.
Ćuk converter – Wikipedia
The following discussion highlights differences between inverting power supply architectures, with an emphasis on intuitive thought rather than in-depth power supply design and switching theory. The objective is to show the advantages and trade-offs for the Cuk and inverting charge pump, followed by a brief discussion of the inverting topology, so you can make a more informed choice when selecting a negative output circuit topology that best suits your application.
It features a wide 4. It requires two inductors these can be coupled or uncoupled and are typically matched in value and a coupling capacitor C5 between the input and output. The coupling or blocking capacitor receives energy from the input side of the circuit and transfers it to the output side of the circuit.
With steady-state conditions i. The LT is a multitpology switching regulator with a 3. Note that the two circuits look very similar; with the exception being the Cuk’s second inductor has been replaced by a Schottky diode. The lowside switch is also used in boost, SEPIC and flyback topologies, so these devices are quite versatile. The switch node always has a positive voltage applied to it. In a Cuk design, the feedback pin may or may not see a negative voltage some devices do not allow negative voltages anywhere on the IC, some devices have a dual mode feedback pin that accepts both positive and negative voltages.
Though similar in appearance, the operation of the two circuits is quite different. For the Cuk, the simplified duty cycle assuming lossless diodes and switches is given by:.
The current flowing from the input power source is continuous in other words, current flows from the input when the power switch is closed or open. When the switch is closed, both inductors have an increasing current flow the current is ramping up, but since the current in L2 is negative the two currents ramps move in opposite directions.
The current in both inductors decreases when the switch opens. Continuous current flow combined with the LC filters results in a smoother input and output current, which in turn gives low output voltage ripple noise. The inverting charge pump is closely related to a step-up converter because it combines an inductor-based step-up regulator with an inverting charge pump. To this circuitry we add diodes and capacitors to obtain the inverting charge pump converter. This configuration often provides the best combination of size, efficiency and output ripple for a given output current.
Differences Between the Ćuk Converter and the Inverting Charge Pump Converter | Analog Devices
Though it uses a charge pump, fairly high load currents can be obtained because the inductor is the main energy storage element rather than a flying capacitor.
Figure 7 below shows the LTused as an inverting charge pump upper circuit conevrtidor a boost converter.
Output disconnect is inherently built into this single inductor topology. The resistor values recommended in the applications circuit also limit the switch current convettidor a short-circuit condition at the output. The inverting topology uses a single inductor and does not require a coupling capacitor; thus it requires fewer components as shown below.
Convertdor example of the single inductor inverting topology is shown in figure 9 below using the LTC inverting controller with external power switch.
The LTC has a 3. Since the power switch must see a negative voltage, the inverting topology is less versatile in that it can only be used for negative voltages.
It also has higher peak current and output ripple than a Cuk converter with a similar output current. Let’s look at the current flow during switching cycles for each topology. For the inverting converter, current flows from the input power source only when the switch is closed. This results in a pulsed input current rather than continuous current flow. Since we are dealing with power transfer, as the output voltage becomes more negative or the input voltage decreases, the peak inductor current increases, increasing output ripple noise; similarly, as the input voltage increases or the output voltage approaches 0V, the peak inductor current decreases.
In both cases, the inductor current can be continuous and the input current can approach being continuous, but it never is continuous.
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Another difference between the topologies is the voltage at the switch node. For the inverting converter, this voltage is negative during the 2nd phase of the switch cycle. Therefore the topologies are not readily convertible from one to the other. In addition to these circuits, the buck converter with the output referenced to ground, and the flyback converter are also capable of providing a negative output voltage.
Unfortunately, many data sheets and online search parametric tables do not distinguish between the unique topologies, but rather lump them together as “inverting converters. He has been in the semiconductor industry for 26 years in applications, business management and marketing roles. In his rarely available brief moments of spare time, he writes bios and ponders what he would do if he had more spare time.
He joined Linear Technology now a part of ADI in as an associate engineer and was promoted to applications engineer in He received an associate degree in electronics from Bay Valley Technical Institute in Please Select a Region.
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