Led Lighting Drive Solution
there Are Two General Drive Schemes: Linear Drive And Switch Drive.
linear Drive Applications Are One Of The Simplest And Most Direct Drive Applications. In Lighting-level White Led Applications, There Are Problems Such As Low Efficiency And Poor Adjustability, But Due To Its Simple Circuit And Small Size, It Can Meet More Specific Applications.
switching Drives Can Achieve Good Current Control Accuracy And High Overall Efficiency. Application Methods Are Mainly Divided Into Two Categories: Buck And Boost. The Step-down Switching Drive Is For Applications Where The Supply Voltage Is Higher Than The Led's Terminal Voltage Or Where Multiple Leds Are Driven In Parallel. The Step-up Switching Driver Is For Applications Where The Supply Voltage Is Lower Than The Led's Terminal Voltage Or When Multiple Leds Are Used In A Series Drive.
it Is Generally Believed That Isolated Drives Are Safe But Less Efficient, And Non-isolated Drives Are More Efficient. They Should Be Selected Based On Actual Requirements.
designing A Basic Led Driver For General Lighting Applications Is Relatively Simple, But If Other Functions Such As Phase-controlled Dimming And Power Factor Correction (pfc) Are Also Required, The Design Becomes Complicated. Non-dimmable Led Drivers Without Power Factor Correction Usually Include An Off-line Switching Power Supply For Regulating Output At Constant Current.
the Back-end Architecture Of The Led Driver Includes A Current Regulation Circuit With Short-circuit Protection. Linear Adjustment Circuits Can Be Used To Achieve This Goal. However, This Approach Is Inherently Inefficient And Therefore Suitable For Low Output Currents. It Is Not Usually Applied To Multi-level Architectures. The Alternative Is To Use A Simple Buck Regulator Circuit With Current Feedback To Limit The Output Current Beyond The Desired Led Drive Current. This Offsets The Change In Total Led Forward Voltage With Temperature And Device Tolerance, And Also Limits The Current In The Event Of A Short Circuit Or Other Fault Condition, Thereby Protecting The Driver From Damage.
