LM5145 datasheet(21/70 Pages) TI

21 / 70 page

transconductance of 30 µS. Internal compensation is configured by connecting the EXTCOMP pin through

a 10-kΩ resistance to VDDA. If a 10-kΩ resistor is not detected, the LM5148 defaults to the external loop

compensation network. The transconductance of the amplifier for external compensation is 1200 µS. This is

latched and cannot be reconfigured after programmed unless power to the device is recycled. Use an external

compensation network if higher performance is required to meet a stringent transient response specification. To

reconfigure the compensation (internal or external), remove power and allow VCC to drop below its VCCUVLO

threshold, which is 3.3 V (typical).

TI generally recommends a type-II compensation network for peak current-mode control.

8.3.11 Slope Compensation

The LM5148 provides internal slope compensation for stable operation with peak current-mode control and a

duty cycle greater than 50%. Calculate the buck inductance to provide a slope compensation contribution equal

to one times the inductor downslope using Equation 9.

OUT

O-IDEAL

(V) R (m )

( +

24 F

(MHz)

(9)

• A lower inductance value generally increases the peak-to-peak inductor current, which minimizes size and

cost, and improves transient response at the cost of reduced light-load efficiency due to higher cores losses

and peak currents.

• A higher inductance value generally decreases the peak-to-peak inductor current, reducing switch peak and

RMS currents at the cost of requiring larger output capacitors to meet load-transient specifications.

8.3.12 Inductor Current Sense (ISNS+, VOUT)

There are two methods to sense the inductor current of the buck power stage. The first uses a current sense

resistor (also known as a shunt) in series with the inductor, and the second avails of the DC resistance of the

inductor (DCR current sensing).

8.3.12.1 Shunt Current Sensing

Figure 8-4 illustrates inductor current sensing using a shunt resistor. This configuration continuously monitors the

inductor current to provide accurate overcurrent protection across the operating temperature range. For optimal

current sense accuracy and overcurrent protection, use a low inductance ±1% tolerance shunt resistor between

the inductor and the output, with a Kelvin connection to the LM5148 current sense amplifier.

If the peak voltage signal sensed from ISNS+ to VOUT exceeds the current limit threshold of 60 mV, the current

limit comparator immediately terminates the HO output for cycle-by-cycle current limiting. Calculate the shunt

resistance using Equation 10.

CS-TH

OUT(CL)

(10)

where

• VCS-TH is current sense threshold of 60 mV.

• IOUT(CL) is the overcurrent setpoint that is set higher than the maximum load current to avoid tripping the

overcurrent comparator during load transients.

• ΔIL is the peak-to-peak inductor ripple current.

www.ti.com

LM5148

SNVSC01 – FEBRUARY 2023

Submit Document Feedback

Product Folder Links: LM5148

LM5145 датащи(PDF) 21 Page - Texas Instruments

LM5145 датащи(HTML) 21 Page - Texas Instruments

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70

датащи скачать

ссылки URL