FUNCTIONAL DESCRIPTION
FUNCTIONAL INTERNAL BLOCK DESCRIPTION
VVB+ (21 V to 42 V)
34920
VB+
V1_SWITCH
VV1
V1 Regulator
V2 Regulator
V1_FB
VB+
Oscillator
V2_SWITCH
VV2
V2_FB
ENABLE
Oscillator
VVB+ (21 V to 42 V)
22 µF 25 V
VB
CP1
Vb Generator
10 nF 50 V
CP2
Figure 6. Voltage Regulator Functions
VOLTAGEREGULATOR OUTPUTREQUIREMENTS
Table 10 provides a listing of the output voltages and currents. Both switchmode converters operate at approximately
200 kHz ±25 kHz.
Table 10. Voltage Regulator Output Requirements
Voltage Name
Minimum Voltage
Maximum Voltage
Load Range
V
-4.0% of Nominal
+4.0% of Nominal
10 mA Min, 500 mA Max DC
V1
(10)
-2.0% of Nominal
+2.0% of Nominal
V
10 mA Min, 1.3 A Max DC (11)
V2
Notes
10. This voltage is programmable within a range of 10 V to 15 V via external resistors. The voltage tolerance around any set point is ±2%
of the nominal.
11. Maximum peak duration is 400 ms.
The V1 and V2 regulators provide individual internal over-
temperature sensing for protection. During an overtempera-
respective V1_FB and V2_FB pins. This will result in the
regulator output voltages to be equal to 0 V.
ture event, when the device TJ is at or above TJ(SHUTDOWN)
,
the internal thermal protection circuit disables the drive
OVERCURRENT PROTECTION
outputs by driving all outputs to the zero current state until the
device temperatures have dropped below the lower thermal
threshold temperature TJ(ENABLE), at which time the driver is
Output voltages VV1 and VV2 are short circuit protected.
The outputs respond to an overcurrent situation by limiting
the internal switching duty cycle. This can be reset by
removing the main supply to the chip or when the short circuit
condition is removed. Refer to the respective IOC and ISC
re-enabled.
The V1 and V2 voltage regulators may be shut down by
applying a voltage in the range of 3.0 V to 6.0 V to the
34920
Analog Integrated Circuit Device Data
Freescale Semiconductor
18
FREESCALE [ Freescale ]
