The reference design is for a DC-DC converter which employs a flyback topology and supplies galvanic isolation thus making it appropriate for delicate purposes.
Do you need to construct your personal DC-DC converter which is powerful, environment friendly and protected on your delicate equipments? Then this reference design from Microchip will make it easier to construct your remoted flyback converter that may take enter from a USB output and supply a relentless and dependable output.
The MCP1661 Flyback Converter Reference Design from Microchip is an remoted flyback converter that provides galvanic isolation. The MCP1661 is a continuing Pulse-Width Modulation (PWM) frequency enhance (step-up) converter, based mostly on a Peak Present mode structure which delivers excessive effectivity over a large load vary from two-cell and three-cell Alkaline, Energizer Final Lithium, NiMH, NiCd and single-cell Li-Ion battery inputs. A excessive degree of integration lowers complete system value, eases implementation, and reduces board space.
The galvanic isolation supplied by the board is a security approach utilized in electrical programs the enter and output circuits electrically whereas nonetheless permitting them to speak or change energy. It entails using a transformer or optocoupler to electrically isolate the first and secondary sides of a circuit, thus stopping the circulation {of electrical} present between them. Galvanic isolation is usually utilized in purposes the place security is a major concern, corresponding to in medical units, energy provides, and industrial management programs. It will also be used to scale back noise and interference between circuits, in addition to to guard delicate digital elements from high-voltage or high-current spikes that will happen on the enter aspect.
MCP1661 has been developed for purposes that require larger output voltage capabilities. MCP1661 can regulate the output voltage as much as 32V and ship 125 mA typical load at 3.3V enter and 12V output. At mild hundreds, MCP1661 skips pulse to maintain the output voltage in regulation, however the voltage ripple is maintained low. The regulated output voltage must be higher than the enter voltage. The circuit diagram of the reference design is proven beneath:
This software makes use of MCP1661 as an open-loop flyback converter, the first winding of the transformer getting used as an inductor for the enhance converter that clamps the first output voltage (VOUTP) at round 13.5V. It’s important (for the traditional operation of all the circuitry and to keep away from damaging some digital elements) to not join any extra load between VOUTP and GND. The output voltage of the flyback converter (VOUTS) drops with the rise of output present for the reason that suggestions is taken from the first aspect. To realize an excellent output voltage regulation within the secondary aspect (VOUT), a 5V LDO is positioned after the rectifying diode of the flyback converter, subsequently the lower of VOUTS when growing the load shouldn’t be important. The MCP1661 Remoted Flyback Converter Reference Design can be utilized for USB-powered purposes, the place a optimistic, regulated 5V output voltage is required from an remoted enter voltage that varies from 4.75V to five.25V.
Options of MCP1661 Flyback Converter Reference Design
• Enter Voltage: 4.25V – 5.25V, Typical
– USB commonplace enter voltage vary
• Output Functionality:
– Over 200 mA (at VOUT = 5V)
– Galvanic isolation
– Quick-circuit safety
• Effectivity: as much as 75%
• PWM Operation at 500 kHz
Microchip has examined this reference design. The corporate has additionally offered extra sources corresponding to schematics, Gerber information, and many others. Yow will discover extra knowledge in regards to the reference design on the corporate’s web site. To learn extra about this reference design click on right here.
