Electronic Components Datasheet Search |
|
LM5010SDX Datasheet(PDF) 10 Page - Texas Instruments |
|
LM5010SDX Datasheet(HTML) 10 Page - Texas Instruments |
10 / 26 page 'I = (VIN - VOUT) x tON L1 V IN STOP R ON /SD R ON Input Voltage LM5010 RUN LM5010 SNVS307E – SEPTEMBER 2004 – REVISED FEBRUARY 2005 www.ti.com The inverse relationship of tON vs. VIN results in a nearly constant frequency as VIN is varied. If the application requires a high frequency the minimum value for tON, and consequently RON, is limited by the off-time (265 ns, ±15%) which limits the maximum duty cycle at minimum VIN. The tolerance for Equation 5 is ±25%. Frequencies in excess of 1 MHz are possible with the LM5010. Shutdown The LM5010 can be remotely shut down by taking the RON/SD pin below 0.65V. See Figure 11. In this mode the soft start pin is internally grounded, the on-timer is disabled, and the input current at VIN is reduced (Figure 7). Releasing the RON/SD pin allows normal operation to resume. When the switch is open, the nominal voltage at RON/SD is shown in Figure 6. Figure 11. Shutdown Implementation Current Limit Current limit detection occurs during the off-time by monitoring the recirculating current through the free-wheeling diode (D1). The detection threshold is 1.25A, ±0.25A. Referring to Typical Application Circuit and Block Diagram, when the buck switch is off the inductor current flows through the load, into SGND, through the sense resistor, out of ISEN and through D1. If that current exceeds the threshold the current limit comparator output switches to delay the start of the next on-time period. The next on-time starts when the current out of ISEN is below the threshold and the voltage at FB is below 2.5V. If the overload condition persists causing the inductor current to exceed the threshold during each on-time, that is detected at the beginning of each off-time. The operating frequency is lower due to longer-than-normal off-times. Figure 12 illustrates the inductor current waveform. During normal operation the load current is IO, the average of the ripple waveform. When the load resistance decreases the current ratchets up until the lower peak attempts to exceed the threshold. During the Current Limited portion of Figure 12, the current ramps down to the threshold during each off-time, initiating the next on-time (assuming the voltage at FB is < 2.5V). During each on-time the current ramps up an amount equal to: (6) During this time the LM5010 is in a constant current mode, with an average load current (IOCL) equal to the threshold + ΔI/2. The “valley current limit” technique allows the load current to exceed the current limit threshold as long as the lower peak of the inductor current is less than the threshold. 10 Submit Documentation Feedback Copyright © 2004–2005, Texas Instruments Incorporated Product Folder Links: LM5010 |
Similar Part No. - LM5010SDX |
|
Similar Description - LM5010SDX |
|
|
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 |