Agilent Technologies 6015A Quick Reference Guide to Major Circuits Major Function, Operation

Table 4-1. Quick Reference Guide to Major Circuits

Circuit	Major Function	Dependent Circuits		Operation
		Input from	Output to
Bias Power	Provides Bias and	Mains	Control Circuits	Mains voltage at BVS input is
Supply (BPS)	Reference Voltage.			converted to lower voltage levels to
				provide the internal operating voltages
				for the various circuits.
Bias Voltage	Delays the unit's	BVS	Delay Circuit,	Holds all circuits reset until all internal
Detector (BVD)	operation at power-		OVP	voltages are at acceptable levels.
	on.
Timed Delay	Enables power	BVD: DOD	PWM; Relay	Waits for 3 seconds after power-on and
Circuit (TDC)	circuits.			then shuts out inrush current limiting
				resistor. The circuit is triggered by the
				BVD when the + VDC is stable.
Power Limit	Determines	BVS; Ramp	PWM	Compares VIP RAMP with VREF and
Comparator (PLC)	maximum primary			produces a signal to inhibit the PWM
	current.			when V IP RAMP > V REF.
Control Voltage	Regulates the	V IP RAMP Control	PWM	Compares VIP RAMP with VCP and
Comparator	operation of the	Port Voltage (VCP)		produces a signal to inhibit the PWM
(CVC)	PWM.			when VIP RAMP > VCP.
Constant Voltage	Produces CV	Outer Voltage	CVC,	Monitors OVS signals from which
Circuit (CV)	Control Voltage.	Sense (OVS)	Display	VMON is derived. Combines OVS and
		Innerloop Voltage	Circuits	IVS to give CV Control Voltage.
		Sense (IVS) CV
		Program Voltage
Constant Current	Produces CC	Outer Current	CVC; Display	Monitors OCS signals from which
Circuit (CC)	Control Voltage.	Sense (OCS). CC	Circuits	l-MON is derived. Combines OCS and;
		Program Voltage		differentiated IVS to give the CC
				control voltage.
Pulse Width	Switches FETs.	Master Enable;	FETs	Switching action achieved at 20KHz
Modulator (PWM)		PLC, CVC		rate with on-pulse activated by 20KHz
				clock and off-pulse by CVC, PLC,
				20KHz clock or shutdown circuits.
Primary Current	Generates IP Ramp	FETs	CVC; PLC	Senses Ip current build-up while FETs
Monitor	Voltage.			are on.
Transformer
Power	Stores and transfers	FETs	Output Rectifier	When FETs are on, the primary
Transformer	output power.			windings of the transformer store
				energy until the FETs are switched off
				when the energy is transferred to the
				secondary for output circuits.
A4 Q1,2,3,4	Control gating of	PWM	Sensing	FETs open and close in response to
	current in power,		Transformer	pulses from the PWM. The length of its
	and Sense			on/off time depends on the duration of
	Transformers.			the PWM on or off pulse.
Down	Rapidly lowers	CV Circuit, OVP,	Output Rail	Output filter capacitor are rapidly
Programmer (DP)	output voltage.	DOD		discharged at varying ampere rates
				depending on output voltage. Circuit
				activated under condition of ac power
				loss, shut down or low voltage.

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