Electronic Components Datasheet Search |
|
YB1517ST25 Datasheet(PDF) 8 Page - YOBON TECHNOLOGIES,INC. |
|
YB1517ST25 Datasheet(HTML) 8 Page - YOBON TECHNOLOGIES,INC. |
8 / 10 page YB1517 Step-up DC-DC Converter & White LED Driver YB1517 Rev.1.4 www.yobon.com.tw 8 Function Block Figure 4: YB1517 Block Diagram Operation The YB1517 uses a constant frequency, current mode control scheme to regulate the output voltage. Its operation can be understood by referring to the block diagram in Figure 4. At the start of each oscillator cycle, a voltage proportional to the switch current is added to a ramp output and the resulting sum is fed into the positive terminal of the PWM comparator (comparator-1). When this voltage exceeds the level of the comparator negative input, the peak current has been reached, and the SR latch (in Control Logic) is reset and turns off the power switch. The voltage at the negative input of the comparator comes from the output of the error amplifier. The error amplifier sets the correct peak current level to keep the output in regulation. If the error amplifier’s output increases, more current is delivered to the output; if it decreases, less current is delivered. Application Information Soft Start and Current Limit The internal soft start circuit minimizes the inrush current during turning on YB1517. The maximum switch current is limited to about 900mA by the chip. Over Voltage Protection The YB1517 has an internal over voltage protection circuit which also acts as an open-circuit protection. In the cases of open circuit or the LEDs failure, the LEDs are disconnected from the circuit, and the feedback voltage will be zero. The YB1517 will then switch to a high duty cycle resulting in a high output voltage, which may cause SW pin voltage to exceed its maximum 24V rating. The YB1517 will shutdown automatically until input condition changes to bring it out of the shutdown mode. |
Similar Part No. - YB1517ST25 |
|
Similar Description - YB1517ST25 |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.NET |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |