MP1410ES-Z データシートの表示（PDF） - Monolithic Power Systems

部品番号

コンポーネント説明

一致するリスト

MP1410ES-Z

2A Step-Down Switch-Mode Regulator

Monolithic Power Systems 

Monolithic Power Systems

Application Information (Continued)

This should be approximately one-fifth of the

switching frequency or approximately fC =

75kHz. This and the loop gain determines the

frequency of the dominant pole, fP1 = fC / AVL.

The dominant pole occurs when GM / 2* π * fP1

* CC = AEA, where GM is the error amplifier

transconductance.

This CC can be

determined by:

CC ~= 306 * AVL / fC ~= 6.8 / ILOAD(MAX) (nF).

The zero of the compensation network is

determined by the compensation resistor RC.

RC should be at the same frequency as the

pole due to the output capacitor and the load

resistor. Or:

RC * CC = RL * COUT

Solving for RC:

RC = RL * COUT / CC = VOUT * COUT / ILOAD(MAX) * CC

If non-ceramic capacitors are used, the second

compensation capacitor is required to

compensate for the zero formed from the

capacitor and its ESR. The second

compensation capacitor can be determined by:

RC * CCA = COUT * RESR

Solving for CCA:

CCA = COUT * RESR / RC.

Inductor

The inductor is required to supply constant

current to the output load while being driven by

the switched input voltage. A larger value

inductor will result in less ripple current that will

MP1410

2A Step-Down

Switch-Mode Regulator

PRELIMINARY

result in lower output ripple voltage. However,

the larger value inductor will have a larger

physical size, higher series resistance, and/or

lower saturation current. Choose an inductor

that will not saturate under the worst-case load

conditions.

Table 2 provides a list of manufacturer’s and

their websites.

Table 2: Inductor Manufacturers

# Manufacturer

1 Sumida Corporation

2 Toko, Inc.

3 Coilcraft, Inc.

Website

www.sumida.com

www.toko.com

www.coilcraft.com

A good rule for determining the inductance to

use, is to allow the peak-to-peak ripple current

in the inductor to be approximately 30% of the

maximum load current. Also, make sure that

the peak inductor current (the load current plus

half the peak-to-peak inductor ripple current) is

below the 2.4A minimum current limit.

The inductance value can be calculated by the

equation:

L = (VOUT) * (VIN-VOUT) / VIN * f * ∆I

Where VOUT is the output voltage, VIN is the

input voltage, f is the switching frequency, and

∆I is the peak-to-peak inductor ripple current.

Table 3 gives a list of inductors for the various

inductor manufacturers.

MP1410 Rev 1.0_ 05/29/02

www.monolithicpower.com

6

Share Link: