UBA2030T Ver la hoja de datos (PDF) - Philips Electronics

Número de pieza

componentes Descripción

Fabricante

UBA2030T

Full bridge driver IC

Philips Electronics 

Philips Semiconductors

Full bridge driver IC

Preliminary specification

UBA2030T

FUNCTIONAL DESCRIPTION

Supply voltage

The UBA2030T is powered by a single supply voltage

connected to the HV pin (the full bridge supply could be

used, for example). The IC generates its own low voltage

supply for driving the internal circuitry and the MOSFETs

in the full bridge, removing the need for an additional low

voltage supply. A capacitor must be connected between

the VDD pin and SGND to obtain a ripple-free internal

supply voltage.

Start-up

When the power is turned on, the UBA2030T enters a

start-up phase; the high side MOSFETs are switched off

and the low side MOSFETs switched on. During start-up,

the bootstrap capacitors are charged and the bridge output

current is zero.

Oscillation

At the point where the supply voltage at the HV pin crosses

the ‘start oscillating threshold’, the bridge begins

commutating between the following two defined states:

Higher left and lower right MOSFETs on,

higher right and lower left MOSFETs off

Higher left and lower right MOSFETs off,

higher right and lower left MOSFETs on.

When the internal oscillator is used, the bridge

commutating frequency is determined by the values of an

external resistor and capacitor. In this mode, the EXO pin

must be connected to SGND.

When an external oscillator is used, its output must be

connected to the EXO pin; the internal oscillator must be

disabled by connecting the RC pin to SGND. The bridge

commutating frequency is half the oscillator frequency due

to a ÷2 circuit which guarantees an accurate 50% duty

factor.

The time between turning off the conducting pair of

MOSFETs and turning on the other pair, the ‘dead time’,

can be adjusted using an external resistor. If the supply

voltage at the HV pin falls below the ‘stop oscillating

threshold’, the UBA2030T re-enters the start-up phase.

Bridge enable

The bridge enable function allows the bridge to be held in

its current state. When active, it connects the RC pin to

SGND, disabling the internal oscillator. If the bridge enable

function is activated during ‘dead time’, the bridge is

allowed to enter the next conducting state before being

held. Oscillations resume the instant the bridge enable

function is turned off. A timing diagram is shown in Fig.3.

To hold the bridge, an external control circuit is required to

provide a source current to the bridge enable control input

(pin BE), and to supply a reference voltage to pin BER,

(see Fig.6).

Shut-down

The active HIGH shut-down input (pin SD) can be used at

any time to turn off all four MOSFETs. However, if the

supply voltage drops below the ‘stop oscillating threshold’,

the bridge re-enters the start-up phase even if the

shut-down function is active.

1999 Aug 10

6

Share Link: