Electronic Components Datasheet Search |
|
MP2234 Datasheet(PDF) 11 Page - Monolithic Power Systems |
|
MP2234 Datasheet(HTML) 11 Page - Monolithic Power Systems |
11 / 21 page MP2234 – SYNCHRONOUS STEP-DOWN CONVERTER MP2234 Rev. 1.0 www.MonolithicPower.com 11 5/16/2013 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2013 MPS. All Rights Reserved. Figure 3 : Adjustable UVLO Soft-Start Adjust the soft-start time by connecting a capacitor from SS pin to ground. When the soft- start begins, an internal 11µA current source charges the external capacitor. During soft- start, the soft-start capacitor connects to the non-inverting input of the error amplifier. The soft-start period continues until the voltage on the soft-start capacitor exceeds the 0.8V reference. Then the non-inverting amplifier uses the reference voltage takes as the input. Use the following equation to calculate the soft-start time: SS 0.8V Css(nF) t (ms) 11 A Power Save Mode for Light Load Condition The MP2234 has AAM (Advanced Asynchronous Modulation) power save mode for light load. The AAM voltage is set at 0.6V internally. Under the heavy load condition, the VCOMP is higher than VAAM. When clock goes high, the high-side power MOSFET turns on and remains on until VILsense reaches the value set by the COMP voltage. The internal clock resets every time when VCOMP is higher than VAAM. Under the light load condition, the value of VCOMP is low. When VCOMP is less than VAAM and VFB is less than VREF, VCOMP ramps up until it exceeds VAAM, during this time, the internal clock is blocked, thus the MP2234 skips some pulses for PFM (Pulse Frequency Modulation) mode and achieves the light load power save. Figure 4: Simplified AAM Control Logic When the load current is light, the inductor peak current is set internally which is about 0.9A for VIN=12V, VOUT=3.3V, and L=4.7μH. Over-Current-Protection and Hiccup The MP2234 has a cycle-by-cycle over-current limit when the inductor current peak value exceeds the set current limit threshold. Meanwhile, the output voltage drops until VFB is below the Under-Voltage (UV) threshold — typically 50% below the reference. Once UV is triggered, the MP2234 enters hiccup mode to periodically restart the part. This protection mode is especially useful when the output is dead-shorted to ground, and greatly reduces the average short circuit current to alleviate thermal issues and protect the regulator. The MP2234 exits the hiccup mode once the over- current condition is removed. Thermal Shutdown Thermal shutdown prevents the chip from operating at exceedingly high temperatures. When the silicon die reaches temperatures that exceed 150°C, it shuts down the whole chip. When the temperature drops below its lower threshold, typically 130°C, the chip is enabled again. Floating Driver and Bootstrap Charging An external bootstrap capacitor powers the floating power MOSFET driver. This floating driver has its own UVLO protection. This UVLO’s rising threshold is 2.2V with a hysteresis of 150mV. The bootstrap capacitor voltage is regulated internally by VIN through D1, M1, R3, C4, L1 and C2 (Figure 5). If (VIN- VSW) exceeds 5V, U1 will regulate M1 to maintain a 5V BST voltage across C4. A 2 0Ω resistor placed between SW and BST cap. is strongly recommended to reduce SW spike voltage. |
Similar Part No. - MP2234 |
|
Similar Description - MP2234 |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.COM |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Datasheet Upload | 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 |