công cụ tìm kiếm bảng dữ liệu linh kiện điện tử |
|
LM5576QMHX/NOPB bảng dữ liệu(PDF) 11 Page - Texas Instruments |
|
|
LM5576QMHX/NOPB bảng dữ liệu(HTML) 11 Page - Texas Instruments |
11 / 27 page Sample and Hold DC Level 0.5V/A RAMP TON tON CRAMP (5P x (VIN ± VOUT) + 25P) x LM5576Q0 www.ti.com SNOSB24B – OCTOBER 2008 – REVISED APRIL 2013 Figure 14. Composition of Current Sense Signal The sample & hold DC level illustrated in Figure 14 is derived from a measurement of the re-circulating Schottky diode anode current. The re-circulating diode anode should be connected to the IS pin. The diode current flows through an internal current sense resistor between the IS and PGND pins. The voltage level across the sense resistor is sampled and held just prior to the onset of the next conduction interval of the buck switch. The diode current sensing and sample & hold provide the DC level of the reconstructed current signal. The positive slope inductor current ramp is emulated by an external capacitor connected from the RAMP pin to AGND and an internal voltage controlled current source. The ramp current source that emulates the inductor current is a function of the Vin and Vout voltages per the following equation: IRAMP = (5µ x (Vin – Vout)) + 25µA (2) Proper selection of the RAMP capacitor depends upon the selected value of the output inductor. The value of CRAMP can be selected from: CRAMP = L x 10 -5 where • L is the value of the output inductor in Henrys. (3) With this value, the scale factor of the emulated current ramp will be approximately equal to the scale factor of the DC level sample and hold (0.5 V / A). The CRAMP capacitor should be located very close to the device and connected directly to the pins of the IC (RAMP and AGND). For duty cycles greater than 50%, peak current mode control circuits are subject to sub-harmonic oscillation. Sub-harmonic oscillation is normally characterized by observing alternating wide and narrow pulses at the switch node. Adding a fixed slope voltage ramp (slope compensation) to the current sense signal prevents this oscillation. The 25µA of offset current provided from the emulated current source adds some fixed slope to the ramp signal. In some high output voltage, high duty cycle applications, additional slope may be required. In these applications, a pull-up resistor may be added between the VCC and RAMP pins to increase the ramp slope compensation. Copyright © 2008–2013, Texas Instruments Incorporated Submit Documentation Feedback 11 Product Folder Links: LM5576Q0 |
Số phần tương tự - LM5576QMHX/NOPB |
|
Mô tả tương tự - LM5576QMHX/NOPB |
|
|
Link URL |
Chính sách bảo mật |
ALLDATASHEET.VN |
Cho đến nay ALLDATASHEET có giúp ích cho doanh nghiệp của bạn hay không? [ DONATE ] |
Alldatasheet là | Quảng cáo | Liên lạc với chúng tôi | Chính sách bảo mật | Trao đổi link | Tìm kiếm theo nhà sản xuất 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 |