NCV8870 datasheet(10/16 Pages) ONSEMI

Part #	NCV8870

Description	Automotive Grade Non-Synchronous Boost Controller

Download	16 Pages

Scroll/Zoom	100%

Manufacturer	ONSEMI [ON Semiconductor]

Direct Link	http://www.onsemi.com

Logo

10 / 16 page

NCV8870

www.onsemi.com

10

7. Select Compensator Components

Current Mode control method employed by the NCV8870

allows the use of a simple, Type II compensation to optimize

the dynamic response according to system requirements.

8. Select MOSFET(s)

In order to ensure the gate drive voltage does not drop out

the MOSFET(s) chosen must not violate the following

inequality:

Q

g(total) v

I

drv

fs

Where: Qg(total): Total Gate Charge of MOSFET(s) [C]

Idrv: Drive voltage current [A]

fs: Switching Frequency [Hz]

The maximum RMS Current can be calculated as follows:

I

Q(max) + Iout

D

The maximum voltage across the MOSFET will be the

maximum output voltage, which is the higher of the

maximum input voltage and the regulated output voltaged:

V

Q(max) + VOUT(max)

9. Select Diode

The output diode rectifies the output current. The average

current through diode will be equal to the output current:

I

D(avg) + IOUT(max)

Additionally, the diode must block voltage equal to the

higher of the output voltage and the maximum input voltage:

V

D(max) + VOUT(max)

The maximum power dissipation in the diode can be

calculated as follows:

P

D + Vf (max) IOUT(max)

Where: Pd: Power dissipation in the diode [W]

Vf(max): Maximum forward voltage of the diode [V]

10. Determine Feedback Loop Compensation Network

The purpose of a compensation network is to stabilize the

dynamic response of the converter. By optimizing the

compensation network, stable regulation response is

achieved for input line and load transients.

Compensator design involves the placement of poles and

zeros in the closed loop transfer function. Losses from the

boost inductor, MOSFET, current sensing and boost diode

losses

also

influence

the

gain

and

compensation

expressions. The OTA has an ESD protection structure

(RESD

≈ 502 W, data not provided in the datasheet) located

on the die between the OTA output and the IC package

compensation pin (VC). The information from the OTA

PWM feedback control signal (VCTRL) may differ from the

IC-VC signal if R2 is of similar order of magnitude as RESD.

The compensation and gain expressions which follow take

influence from the OTA output impedance elements into

account

.

Type-I compensation is not possible due to the presence

of RESD. The Figures 11 and 12 compensation networks

correspond to a Type-II network in series with RESD.

The resulting control-output transfer function is an accurate

mathematical model of the IC in a boost converter topology.

The model does have limitations and a more accurate SPICE

model should be considered for a more detailed analysis:

• The attenuating effect of large value ceramic capacitors

in parallel with output electrolytic capacitor ESR is not

considered in the equations

.

• The CCM Boost control-output transfer function

includes operating efficiency as a correction factor to

improve modeling accuracy under low input voltage

and high output current operating conditions where

operating losses becomes significant.

Similar Part No. - NCV8870

Manufacturer	Part #	Datasheet	Description
ON Semiconductor	NCV8870	143Kb / 11P	Automotive Grade Non-Synchronous Boost Controller September, 2012 ??Rev. 1
	NCV887000	143Kb / 11P	Automotive Grade Non-Synchronous Boost Controller September, 2012 ??Rev. 1
	NCV887000D1R2G	143Kb / 11P	Automotive Grade Non-Synchronous Boost Controller September, 2012 ??Rev. 1
	NCV887000D1R2G	239Kb / 15P	Automotive Grade Non-Synchronous Boost Controller August, 2016 ??Rev. 10
	NCV887001	143Kb / 11P	Automotive Grade Non-Synchronous Boost Controller September, 2012 ??Rev. 1

More results

Similar Description - NCV8870

Manufacturer	Part #	Datasheet	Description
ON Semiconductor	NCV8870	239Kb / 15P	Automotive Grade Non-Synchronous Boost Controller August, 2016 ??Rev. 10
	NCV887200	145Kb / 16P	Automotive Grade Non-Synchronous Boost Controller June, 2015 ??Rev. 7
	NCV8871	242Kb / 17P	Automotive Grade Non-Synchronous Boost Controller August, 2016 ??Rev. 12
	NCV8873	176Kb / 11P	Automotive Grade Non-Synchronous Boost Controller August, 2016 ??Rev. 6
	NCV8871	145Kb / 12P	Automotive Grade Non-Synchronous Boost Controller September, 2012 ??Rev. 3
	NCV8870	143Kb / 11P	Automotive Grade Non-Synchronous Boost Controller September, 2012 ??Rev. 1
	NCV8871	146Kb / 17P	Automotive Grade Non-Synchronous Boost Controller January, 2017 ??Rev. 13
	NCV887200	240Kb / 16P	Automotive Grade Non-Synchronous Boost Controller August, 2016 ??Rev. 9
	NCV8873	101Kb / 11P	Automotive Grade Non-Synchronous Boost Controller December, 2017 ??Rev. 8
	NCV8873	143Kb / 11P	Automotive Grade Non-Synchronous Boost Controller May, 2012 ??Rev. 2

More results

NCV8870 Datasheet(PDF) 10 Page - ON Semiconductor

NCV8870 Datasheet(HTML) 10 Page - ON Semiconductor

Similar Part No. - NCV8870

Similar Description - NCV8870

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Datasheet Download

Link URL