tea1506 NXP Semiconductors, tea1506 Datasheet - Page 7

• Manufacturer Part Number: tea1506
• Description: Greenchip Smps Control Ic
• Manufacturer: NXP Semiconductors

Philips Semiconductors
2003 Sep 09
handbook, halfpage
handbook, full pagewidth
GreenChip II SMPS control IC
The voltage levels dV
Fig.7 VCO frequency as function of V
CTRL
(kHz)
175
f
25
1.5 V
150 mV
V CTRL
1
V x
and dV
X2
VCO 2
level
2
comparator
are fixed in the IC to 50 mV (typical) and 18 mV (typical) respectively.
current
VCO 1
level
V
I
V sense(max) (V)
OSCILLATOR
175 kHz
DRIVER
MGU509
Fig.8 The cycle skipping circuitry.
sense(max)
.
DRIVER
I sense
7
Cycle skipping
At very low power levels, a cycle skipping mode will be
activated. A high control voltage will reduce the switching
frequency to a minimum of 25 kHz. If the voltage on the
control pin is raised even more, switch-on of the external
power MOSFET will be inhibited until the voltage on the
control pin has dropped to a lower value again (see Fig.8).
For system accuracy, it is not the absolute voltage on the
control pin that will trigger the cycle skipping mode, but a
signal derived from the internal VCO will be used.
Remark: If the no-load requirement of the system is such
that the output voltage can be regulated to its intended
level at a switching frequency of 25 kHz or above, the
cycle skipping mode will not be activated.
f max
f min
f osc
skipping
cycle
1
0
TEA1506P; TEA1506AP;
TEA1506T; TEA1506AT
dV 2
dV 1
Product specification
150
V x (mV)
MGU510
V x (mV)