UCCD PDF datasheet & technical specifications. Download or read online TI (Texas Instruments) UCCD IC CTRLR PWM GREEN CM OVP 8SOIC. The UCC is a PWM controller with advanced Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. Texas Instruments UCCD: available from 21 distributors. Explore Integrated Circuits (ICs) on Octopart: the fastest source for datasheets, pricing.
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The mode of operation depends upon line and load conditions. Thus during cycle-by-cycle power limit, the peak CS voltage is typically 0. This current source adds a proportional step offset power limit offset to the Ucc28600d datasheet signal and is part of the cycle-by-cycle power limit function that is discussed in the Protection Features section. When the bias winding is positive, during demagnetization or portions of the resonant ring, the OVP pin voltage is positive.
In this mode, the flyback converter operates ucc28600d datasheet the boundary of discontinuous conduction mode and continuous conduction ucc28600d datasheet.
Operation in FFM results in the application of constant volt-seconds to the flyback transformer during each switching cycle. The UCC has many ucc28600d datasheet features that are found only on larger, full featured controllers.
The details of the functional boxes also conceptualize uucc28600d various fault detections and responses that are included in the UCC At power limit, the CS pin voltage plus the internal CS offset is compared against a constant darasheet.
Voltage regulation in FFM is achieved by varying ucc28600d datasheet switching frequency in the range from kHz to 40 ucc28600d datasheet.
It also has a datashheet frequency clamp of 40 kHz. It prevents operation when the internal reference is below ucc28600d datasheet. During all modes of operation, this controller operates in current mode control. Soft-start and fault responses are the exception.
UCCD 데이터시트(PDF) – Texas Instruments
CS ucc28600d datasheet I Equation 1. Valley detection is active during FFM. At DCM control, the peak current is adjusted to control the output power.
When the FB voltage ucc28600d datasheet between 1. Operation Mode Switching Frequencies. To a lesser degree yet significantthe boundaries are affected by the MOSFET output capacitance and transformer leakage inductance. As the load increases, the number of pulses in ucc28600d datasheet burst packets increases until the converter ucc28060d switching consistently at 40 kHz, at which point it transitions into the next operating mode, called frequency foldback.
8-Pin Quasi Resonant Flyback Green Mode Controller
Datasheeet frequency foldback mode, as ucc28600d datasheet load decreases, the Ucc28600d datasheet peak current is kept constant and the switching frequency is reduced foldback to reduce the output power. This pin is used to control bias power for a PFC stage, as shown in Figure 9. Advanced logic control coordinates the fault detections to provide proper power supply recovery.
Green mode reduces the average switching frequency in order to minimize switching losses and increase the efficiency at light-load conditions. Resonant valley switching is an integral part of Ucc28600d datasheet operation.
In this mode, the flyback converter will always operate in discontinuous conduction mode. If the OVP voltage is greater than 3. During green mode, the converter operates at a fixed switching frequency ucc28600d datasheet 40 kHz and fixed peak current. Refer ucc28600d datasheet the Functional Block DiagramTypical Application DiagramFigure 6Figure 7Figure 8Figure 10Figure ucc28600d datasheetand Figure 12 for detailed block descriptions that show how the features ucc28600d datasheet integrated into the normal control functions.
The minimum switching frequency of the converter is limited to 40 kHz. The use of the UCC design calculator, SLVCis highly recommended in order to achieve the desired results with a careful balance between the transformer parameters and the programming resistors. These figures conceptualize how the UCC executes the command of the FB voltage to have the responses that are shown in Figure 11Figure 5 and Figure As the load increases, the kHz switching will become consistent and the ucc28600d datasheet will transition to frequency fold-back mode FFMwhere the peak primary current is held constant and the switching frequency is modulated from 40 kHz up to kHz, in order to maintain regulation.
This allows the UCC to monitor the FB voltage to determine and respond to the varying load levels such as heavy, light or ultra-light.
UCC データシート 8 ピン、クアジ・レゾナント・フライバック、グリーン・モード・コントローラ |
During soft start, the converter switching frequency is fixed at ucc28600d datasheet kHz and FB is set to 5V. In order to have power limited over the full line voltage range of the QR Flyback converter, the CS pin voltage must have a component that is proportional to the primary current plus a component that is proportional to the line voltage due to predictable switching frequency ucc28600d datasheet due to line voltage. Resistor R PL results in the addition of a voltage to the current sense signal that is proportional to the line voltage.
Because the device will initiate cycle-by-cycle power limit first, primary side current protection is not intended to protect against output short circuit ucc28600d datasheet.
At this maximum switching frequency, the converter enters DCM control. During this control mode, the rising edge of OUT will occur just after the valley of the resonant ring when the ucc286000d is fully demagnetized. Dataasheet is allowed if the substrate temperature reduces by the hysteresis value. At higher loads, the UCC will operate in either DCM, where the peak primary current is modulated but the switching frequency is maintained at its maximum value, or quasi-resonant mode QRMwhere ucc28600d datasheet switching frequency and the peak primary current are both modulated in order datasheeet maintain regulation.
A cycle-by-cycle power limit imposes ucc28600d datasheet fixed 0. When the primary current exceeds maximum current level which ucc28600d datasheet indicated by a voltage of 1. Ucc28600d datasheet FB reaches 0.